1.PhishCo runs a number of farms in the arid province of Nufa, depending largely on irrigation. Now, as part of a plan to efficiently increase the farms’ total production, it plans to drill down to an aquifer containing warm, slightly salty water that will be used to raise fish in ponds. The water from the ponds will later be used to supplement piped-in irrigation water for PhishCo’s vegetable fields, and the ponds and accompanying vegetation should help reduce the heat in the area of the farms.
Which of the following would, if true, most strongly suggest that the plan, if implemented, would increase the overall efficiency of PhishCo’s farms?(C)
A. Most of the vegetation to be placed around the ponds is native to Nufa.
B. Fish raised on PhishCo’s farms are likely to be saleable in the nearest urban areas.
C. Organic waste from fish in the pond water will help to fertilize fields where it is used for irrigation.
D. The government of Nufa will help to arrange loan financing to partially cover the costs of drilling.
E. Ponds will be located on low-lying land now partially occupied by grain crops.
解析：Evaluation of a Plan
Situation A company plans to increase the total efficiency of its farms in an arid region by drilling down to an aquifer whose water will be used to raise fish in ponds and to help irrigate the farms’ vegetable fields. The ponds and accompanying vegetation should help reduce the heat around the farms.
Reasoning What would make it most likely that implementing the plan would increase the farms’ overall efficiency? The farms will become more efficient if the plan significantly increases their production for little or no added cost.
A Vegetation native to an arid region may be no more likely to thrive around ponds than non-native vegetation would be, and in any case would not clearly increase the farms’ total crop production or efficiency.
B This makes it slightly more likely that the plan would increase the farms’ profitability, not their efficiency or productivity.
C Correct. Fertilizing the fields with the waste while irrigating the crops might significantly improve crop production. But it would cost little or nothing extra, since the waste would already be in the irrigation water. Thus, this feature of the plan would likely enhance the farms’efficiency by increasing their productivity for no significant extra cost.
D This government assistance might slightly reduce the work the company has to do to procure a loan. But probably it would neither increase the farms’ production nor reduce the overall expense of implementing the plan (including the expense incurred by the government).
E If anything, this suggests that the plan might reduce the farms’ efficiency by eliminating productive crop land.
The correct answer is C.
2.The sustained massive use of pesticides in farming has two effects that are especially pernicious. First, it often kills off the pests’ natural enemies in the area. Second, it often unintentionally gives rise to insecticide-resistant pests, since those insects that survive a particular insecticide will be the ones most resistant to it, and they are the ones left to breed.
From the passage above, it can be properly inferred that the effectiveness of the sustained massive use of pesticides can be extended by doing which of the following, assuming that each is a realistic possibility?(B)
A. Using only chemically stable insecticides
B. Periodically switching the type of insecticide used
C. Gradually increasing the quantities of pesticides used
D. Leaving a few fields fallow every year
E. Breeding higher-yielding varieties of crop plants
解析：Evaluation of a Plan
Situation Continued high-level pesticide use often kills off the targeted pests’ natural enemies. In addition, the pests that survive the application of the pesticide may become resistant to it, and these pesticide-resistant pests will continue breeding.
Reasoning What can be done to prolong the effectiveness of pesticide use? It can be inferred that the ongoing use of a particular pesticide will not continue to be effective against the future generations of pests with an inherent resistance to that pesticide. What would be effective against these future generations? If farmers periodically change the particular pesticide they use, then pests resistant to one kind of pesticide might be killed by another. This would continue, with pests being killed of in cycles as the pesticides are changed. It is also possible that this rotation might allow some of the pests’ natural enemies to survive, at least until the next cycle.
A Not enough information about chemically stable insecticides is given to make a sound inference.
B Correct. This statement properly identifies an action that could extend the effectiveness of pesticide use.
C Gradually increasing the amount of the pesticides being used will not help the situation since the pests are already resistant to it.
D Continued use of pesticides is assumed as part of the argument. Since pesticides would be unnecessary ror fallow fields, this suggestion is irrelevant.
E Breeding higher-yielding varieties of crops does nothing to extend the effectiveness of the use of pesticides.
The correct answer is B.
3.Which of the following, if true, most logically completes the argument below?
Manufacturers are now required to make all cigarette lighters child-resistant by equipping them with safety levers. But this change is unlikely to result in a significant reduction in the number of fires caused by children playing with lighters, because children given the opportunity can figure out how to work the safety levers and________.(B)
A. the addition of the safety levers has made lighters more expensive than they were before the requirement was instituted
B. adults are more likely to leave child-resistant lighters than non-child-resistant lighters in places that are accessible to children
C. many of the fires started by young children are quickly detected and extinguished by their parents
D. unlike child-resistant lighters, lighters that are not child-resistant can be operated by children as young as two years old
E. approximately 5,000 fires per year have been attributed to children playing with lighters before the safety levers were required.
Situation Manufacturers must equip all cigarette lighters with child-resistant safety levers, but children can figure out how to circumvent the safety levers and thereby often start fires.
Reasoning What point would most logically complete the argument? What would make it likely that the number of fires caused by children playing with lighters would remain the same? In order for children to start fires using lighters equipped with safety levers, they must be given the opportunity to figure out how the safety levers work and then to use them. They must, that is, have access to the lighters.
A If safety-lever-equipped lighters are more expensive than lighters that are not so equipped, fewer lighters might be sold. This would most likely afford children less access to lighters, thus giving them less opportunity to start fires with them.
B Correct. This statement properly identifies a point that logically completes the argument: it explains why children are likely to have access to lighters equipped with safety levers.
C The speed with which fires are extinguished does not have any bearing on the number of fires that are started.
D This provides a reason to believe that the number of fires started by children will most likely decrease, rather than stay the same: fewer children will be able to operate the lighters, and thus fewer fires are likely to be started.
E This information about how many fires were started by children before safety levers were required does not have any bearing on the question of how many fires are likely to be started by children now that the safety levers are required.
The correct answer is B.
4.Which of the following most logically completes the passage?
A business analysis of the Appenian railroad system divided its long-distance passenger routes into two categories: rural routes and interurban routes. The analysis found that, unlike the interurban routes, few rural routes carried a high enough passenger volume to be profitable. Closing unprofitable rural routes, however, will not necessarily enhance the profitability of the whole system, since________.(A)
A. a large part of the passenger volume on interurban routes is accounted for by passengers who begin or end their journeys on rural routes
B. within the last two decades several of the least used rural routes have been closed and their passenger services have been replaced by buses
C. the rural routes were all originally constructed at least one hundred years ago, whereas some of the interurban routes were constructed recently for new high-speed express trains
D. not all of Appenia’s large cities are equally well served by interurban railroad services
E. the greatest passenger volume, relative to the routes’ capacity, is not on either category of long-distance routes but is on suburban commuter routes
Situation In the Appenian railroad system, interurban routes generally carry enough passengers to be profitable, but few rural routes do.
Reasoning What would suggest that closing unprofitable rural routes would not enhance the railroad system’s profitability? Any evidence that closing the unprofitable rural routes would indirectly reduce the profitability of other components of the railroad system would support the conclusion that closing those rural routes will not enhance the system’s profitability. Thus, a statement providing such evidence would logically complete the passage.
A Correct. This suggests that closing the rural routes could discourage many passengers from traveling on the profitable interurban routes as well, thus reducing the profitability of the railroad system as a whole.
B Even if some of the least used rural routes have already been closed, it remains true that most of the remaining rural routes are too little used to be profitable.
C Closing very old routes would be at least as likely to enhance the railroad system’s profitability as closing newer routes would be.
D Even if there is better railroad service to some large cities than others, closing unprofitable rural routes could still enhance the system’s profitability.
E Even if suburban routes are the most heavily used and profitable, closing underused, unprofitable rural routes could still enhance the system’s profitability.
The correct answer is A.
5.In its search for new technologies for solar energy that can produce lower-cost electricity, Smith-Diatom is developing a new way to make dye-sensitive solar cells, in which photons strike light-sensitive dyes. The process uses diatoms, which are unicellular algae that have silicon shells with a complex structure. First, the organic material is removed, and then the shells are coated with a titanium dioxide film that acts as a semiconductor. The diatoms’ structure results in more photon activity and thus more efficient production of electricity than with current dye-sensitized solar cells, which in turn lowers the cost.
Which of the following considerations would, if true, most strongly support the hypothesis that the plan, if implemented, will produce low-cost electricity from dye-sensitive solar cells?(C)
A. Diatoms are an important link in oceanic food chains and help cycle carbon dioxide from the atmosphere.
B. The current cost of electricity produced by dye-sensitive solar cells is roughly three times that of non-solar electricity.
C. Because diatoms occur naturally, no special engineering processes are needed to produce the basic dye-sensitive solar cell structures.
D. Dye-sensitive solar cells work somewhat more efficiently in lower light than previous solar cell technologies.
E. The production of dye-sensitive solar cells primarily uses materials that do not harm the environment.
解析：Evaluation of a Plan
Situation Smith-Diatom is trying to develop a new way to make dye-sensitive solar cells in hopes of developing a means for using solar energy to produce lower-cost electricity. Their new technology will use diatoms, single-celled algae with silicon shells that have a complex structure. This structure results in increased photon activity, which results in more efficient and lower-cost energy production than current dye-sensitive solar cells do.
Reasoning What statement would provide the strongest support for the claim that Smith-Diatoms plan would result in the production of lower-cost energy than can be attained from the current dye-sensitive solar cells? One potential problem with Smith-Diatom’s plan would be if the intended use of diatoms would be costly. Any statement that ruled out a potentially costly aspects of production, e.g., costly engineering processes, would provide support for the claim in question.
A Nothing in Smith-Diatom’s plan is related to diatom’s connection to oceanic food chains or to their role in cycling carbon dioxide from the atmosphere.
B That producing electricity by means of dye-sensitive solar cells is much more costly than other types of electricity production would help explain why Smith-Diatom wants to find a lower-cost means of producing solar energy, but it does not give us reason to think that Smith-Diatom’s plan will be successful.
C Correct. If no special engineering processes are needed to carry out Smith-Diatom’s plan, one potential costly aspect of solar-electricity production is ruled out, thereby providing some reason to think Smith-Diatom’s goal of producing lower-cost electricity might be attainable.
D The fact that dye-sensitive solar cells work more efficiently in lower light than other solar cell technologies would help support the claim in question only if we knew that the cost of producing such cells is not prohibitive. Also, it could be the case that although dye-sensitive solar cells work more efficiently in lower light than other solar cell technologies, the other solar cell technologies might work much more efficiently in good lighting conditions.
E If the production of dye-sensitive solar cells does not harm the environment, that might be good reason to use such solar cells, but it is not relevant to determining whether Smith-Diatom’s plan will be likely to attain its goal.
The correct answer is C.
6.Although Ackerburg’s subway system is currently operating at a deficit, the transit authority will lower subway fares next year. The authority projects that the lower fares will result in a ten percent increase in the number of subway riders. Since the additional income from the larger ridership will more than offset the decrease due to lower fares, the transit authority actually expects the fare reduction to reduce or eliminate the subway system’s operating deficit for next year.
Which of the following, if true, provides the most support for the transit authority’s expectation of reducing the subway system’s operating deficit?(D)
A. Throughout the years that the subway system has operated, fares have never before been reduced.
B. The planned fare reduction will not apply to students, who can already ride the subway for a reduced fare.
C. Next year, the transit authority will have to undertake several large-scale track maintenance projects.
D. The subway system can accommodate a ten percent increase in ridership without increasing the number of trains it runs each day.
E. The current subway fares in Ackerburg are higher than subway fares in other cities in the region.
Situation Ackerburg’s transit authority plans to lower subway fares, projecting that this will increase ridership by 10 percent and thereby reduce or eliminate the subway system’s operating deficit.
Reasoning What evidence would support the expectation that lowering subway fares will reduce the operating deficit?The passage says the additional income from the projected increase in ridership will more than offset the decrease due to the lowered fares. The claim that lowering fares will reduce the operating deficit could be supported either by additional evidence that lowering the fares will increase ridership at least as much as projected or by evidence that the plan will not increase overall operating expenses.
A The fact that fares have never been reduced provides no evidence about what would happen if they were reduced.
B This suggests that the planned fare reduction would not affect revenue from student riders, but it does not suggest how it would affect revenue from all other riders.
C These maintenance projects will probably increase the operating deficit, making it less likely that the fare reduction will reduce or eliminate that deficit.
D Correct. This indicates that the plan will not involve extra operating expenses for running trains and thus increases the likelihood that the plan will reduce the operating deficit.
E Ackerburg may differ from other cities in the region in ways that make the higher fares optimal for Ackerburg’s subway system.
The correct answer is D.
7.Sparrow Airlines is planning to reduce its costs by cleaning its planes’ engines once a month, rather than the industry standard of every six months. With cleaner engines, Sparrow can postpone engine overhauls, which take planes out of service for up to 18 months. Furthermore, cleaning an engine reduces its fuel consumption by roughly 1.2 percent.
The airline’s plan assumes that(B)
A. fuel prices are likely to rise in the near future and therefore cutting fuel consumption is an important goal
B. the cost of monthly cleaning of an airplane’s engines is not significantly greater in the long run than is the cost of an engine overhaul
C. engine cleaning does not remove an airplane from service
D. Sparrow Airlines has had greater problems with engine overhauls and fuel consumption than other airlines have
E. cleaning engines once a month will give Sparrow Airlines a competitive advantage over other airlines
解析：Evaluation of a Plan
Situation Sparrow Airlines plans to clean the engines of its planes monthly rather than every six months. The goal is to reduce its costs.
Reasoning Which statement provides an assumption underlying the plan? The plan will enable Sparrow to postpone engine overhauls, which put a plane out of service for up to 18 months. The monthly cleaning will reduce its fuel consumption by 1.2 percent. But suppose the long-run cost of monthly cleanings were greater than the cost of an engine overhaul, then the rationale for the airline’s plan would fail.
A Nothing in the information provided indicates that this is assumed in the plan.
B Correct. The plan makes sense only if this is assumed. If the long-run total cost of monthly cleaning significantly exceeded the total cost of engine overhaul—which would include, in the long run, more frequent downtime of 18 months if the plan were not adopted—then it seems likely that the projected benefit of postponement of engine overhauls would not be compensated for by the 1.2 percent fuel-cost savings.
C The plan does not have to assume this. Perhaps monthly engine cleaning requires only one day of down time.
D This is perhaps a good reason for Sparrow to put in place the proposed cost-saving plan, but it is not an assumption that the plan requires for it to make sense.
E The plan does not have to assume this, even if Sparrow’s cost saving were to result in a competitive advantage. Sparrow s plan could equally be aimed at simply removing a competitive disadvantage. The issue of competition is not addressed in the given information.
The correct answer is B.
8.Patrick usually provides child care for six children. Parents leave their children at Patrick’s house in the morning and pick them up after work. At the end of each workweek, the parents pay Patrick at an hourly rate for the child care provided that week. The weekly income Patrick receives is usually adequate but not always uniform, particularly in the winter, when children are likely to get sick and be unpredictably absent.
Which of the following plans, if put into effect, has the best prospect of making Patrick’s weekly income both uniform and adequate?(B)
A. Pool resources with a neighbor who provides child care under similar arrangements, so that the two of them cooperate in caring for twice as many children as Patrick currently does.
B. Replace payment by actual hours of child care provided with a fixed weekly fee based upon the number of hours of child care that Patrick would typically be expected to provide.
C. Hire a full-time helper and invest in facilities for providing child care to sick children.
D. Increase the hourly rate to a level that would provide adequate income even in a week when half of the children Patrick usually cares for are absent.
E. Increase the number of hours made available for child care each day, so that parents can leave their children in Patrick’s care for a longer period each day at the current hourly rate.
解析：Evaluation of a Plan
Situation At the end of the workweek, Patrick is paid a certain amount for each hour of child care he has provided. Patrick usually receives adequate weekly income under this arrangement, but in the winter Patrick’s income fluctuates, because children are unpredictably absent due to illness.
Reasoning Which plan would be most likely to meet the two goals of uniform weekly income and adequate weekly income? Patrick must find a way to ensure that his weekly income is both adequate—that is, no t reduced significantly from current levels—and uniform—that is, not subject to seasonal or other fluctuations. A successful plan would thus most likely be one that does not increase Patrick’s costs. Further, the plan need not increase Patrick’s weekly income; it must merely ensure that that income is more reliable. It should therefore also provide some way to mitigate the unexpected loss of income from children’s absences.
A This plan might raise Patrick’s income slightly, because he and the neighbor might pay out less in costs if they pool their resources. But this plan would have no effect on the problem that unpredictable absences pose for Patrick’s weekly income.
B Correct. This statement properly identifies a plan that would most likely keep Patrick’s income adequate (he would probably receive approximately the same amount of money per child as he does now) and uniform (he would receive the money regardless of whether a child was present or absent).
C While this plan might somewhat mitigate the unpredictability in Patrick’s income that results from sick children’s absences—because parents would be less likely to keep sick children at home—it would increase Patrick’s costs. Paying a helper and investing in different facilities would reduce Patrick’s income and might thus result in that income being inadequate.
D Under this plan, if we assume that parents did not balk at the increase in Patrick’s hourly rate and find alternative child care, Patrick’s income would most likely be adequate. But this plan would not help make Patrick’s weekly income uniform. His income would continue to fluctuate when children are absent. Remember, there are two goals with regard to Patrick’s income: adequacy and uniformity.
E This plan might increase Patrick’s income, in that he might be paid for more hours of child care each week. The goals here, however, are to make Patrick’s weekly income both adequate and uniform, and this plan does not address the issue of uniformity.
The correct answer is B.
9.Editorial: Consumers in North America think that by drinking frozen concentrated orange juice, they are saving energy, because it takes fewer truckloads to transport it than it takes to transport an equivalent amount of not-from-concentrate juice. But they are mistaken, for the amount of energy required to concentrate the juice is far greater than the energy difference in the juices’ transport.
Which of the following, if true, would provide the greatest additional support for the editorial’s conclusion?(A)
A. Freezer trucks use substantially more energy per mile driven than do any other types of trucks.
B. Frozen juice can be stored for several years, while not-from-concentrate juice lasts a much shorter time.
C. Oranges grown in Brazil make up an increasing percentage of the fruit used in not-from-concentrate juice production.
D. A serving of not-from-concentrate juice takes up to six times more space than a serving of frozen concentrated juice.
E. Though frozen concentrated juice must be kept at a lower temperature, not-from-concentrate juice is far more sensitive to small temperature fluctuations.
Situation North American consumers think that drinking frozen concentrated orange juice saves energy because the concentrated juice can be transported in fewer truckloads than an equivalent amount of not-from-concentrate juice. But more energy is required to concentrate the juice than is saved by this reduction in the number of truckloads used for transportation.
Reasoning What additional evidence would most help to support the conclusion that drinking frozen concentrated orange juice rather than not-from-concentrate juice does not save energy? Factors other than the concentration process and the number of truckloads used for transportation may also affect the amounts of energy used to provide the two types of juice. Evidence of any such factor that increases the amount of energy needed to provide frozen concentrated juice more than it increases the amount needed to provide the same amount of not-from-concentrate juice would help to support the editorial’s conclusion.
A Correct. This suggests that it takes much more energy per truckload to transport frozen concentrated juice than to transport not-from-concentrate juice, which is not frozen.
B If anything, this suggests that a higher proportion of not-from-concentrate juice goes bad and is discarded rather than being drunk. This waste would increase the amount of energy used to provide each glass of not-from-concentrate juice that is drunk.
C Since Brazil is far from North America, this suggests that the average amount of energy used to transport each serving of not-from-concentrate juice may be increasing.
D Since both types of juice must be kept cold until ready to drink, this suggests that a much larger amount of space must be refrigerated to provide each serving of not-from-concentrate juice. That may mean that more energy needs to be used to keep each serving of not-from-concentrate juice cold.
E It may take extra energy to keep the temperature of not-from-concentrate juice more constant. If it does, that would increase the amount of energy used to provide each serving of not-from-concentrate juice.
The correct answer is A.
10.A computer equipped with signature-recognition software, which restricts access to a computer to those people whose signatures are on file, identifies a person’s signature by analyzing not only the form of the signature but also such characteristics as pen pressure and signing speed. Even the most adept forgers cannot duplicate all of the characteristics the program analyzes.
Which of the following can be logically concluded from the passage above?(C)
A. The time it takes to record and analyze a signature makes the software impractical for everyday use.
B. Computers equipped with the software will soon be installed in most banks.
C. Nobody can gain access to a computer equipped with the software solely by virtue of skill at forging signatures.
D. Signature-recognition software has taken many years to develop and perfect.
E. In many cases even authorized users are denied legitimate access to computers equipped with the software.
Situation Forgers cannot duplicate all the characteristics that signature-recognition software analyzes, including the form of a signature, pen pressure, and signing speed. Computers equipped with this software restrict access to those whose signatures are on file.
Reasoning What conclusion can be reached about computers equipped with this software? The passage states that the software detects more characteristics in a signature than the most accomplished forger can possibly reproduce. Thus, skill at forging signatures is not enough to allow someone to gain access to a computer equipped with the software.
A No information about the speed of the analysis is given, so no such conclusion can be drawn.
B Although the software would likely be of benefit to banks, we cannot conclude that it will be installed in most banks because the passage doesn’t rule out, e.g., that the software may be too costly or that there may be proprietary constraints.
C Correct. This statement properly identifies a conclusion that can be drawn from the passage.
D Although it seems reasonable to think that the software took a long time to develop, nothing in the passage justifies the claim that it took years.
E Nothing in the passage rules out the possibility that the software functions so well that authorized users will never be denied legitimate access to computers equipped with the software.
The correct answer is C.
11.The rate at which a road wears depends on various factors, including climate, amount of traffic, and the size and weight of the vehicles using it. The only land transportation to Rittland’s seaport is via a divided highway, one side carrying traffic to the seaport and one carrying traffic away from it. The side leading to the seaport has worn faster, even though each side has carried virtually the same amount of traffic, consisting mainly of large trucks.
Which of the following, if true, most helps to explain the difference in the rate of wear?(D)
A. The volume of traffic to and from Rittland’s seaport has increased beyond the intended capacity of the highway that serves it.
B. Wear on the highway that serves Rittland’s seaport is considerably greater during the cold winter months.
C. Wear on the side of the highway that leads to Rittland’s seaport has encouraged people to take buses to the seaport rather than driving there in their own automobiles.
D. A greater tonnage of goods is exported from Rittland’s seaport than is imported through it.
E. All of Rittland’s automobiles are imported by ship.
Situation The side of a divided highway leading to a seaport has worn faster than the side leading away from the seaport. Both sides carry roughly the same amount of traffic, mainly consisting of large trucks.
Reasoning What could explain why the side of the highway leading to the seaport has worn faster than the other side? We are told that climate, amount of traffic, and the size and weight of vehicles on a road affect how quickly the road wears. We are also told that the amounts of traffic on the two sides of the highway are almost identical. Probably the climate on the two sides is also almost identical. Thus, the most likely explanation for the different rates of wear is that the size or weight of the vehicles driving on the two sides differs significantly. So any factor that would make the vehicles’ size or weight greater on the side leading to the seaport than on the other side could help explain the difference in wearing.
A The increased traffic volume affects both sides of the highway, so it does not help explain why one side is wearing faster than the other.
B The winter weather affects both sides of the highway, so it does not help explain why one side is wearing faster than the other.
C The buses may contribute to wear on the side of the highway leading to the seaport, but not necessarily more than the car traffic they are replacing would (though the increased use of buses instead of cars may decrease the amount of traffic, buses would be heavier than cars and thus may result in an equal or greater amount of wear). Furthermore, the buses have to come back on the other side, probably carrying the returning travelers who have not left their cars at the airport.
D Correct. This suggests that the many trucks visiting the seaport tend to be more heavily laden with goods when traveling on the side of the highway leading to the seaport than when returning on the other side. The resulting difference in the trucks’ weight when traveling on the two sides could explain the different rates of wear.
E These automobiles would be transported along the side of the highway leading from the seaport, but not along the side leading to it. This would likely create a pattern of wear opposite to the one observed.
The correct answer is D.
12.Ythex has developed a small diesel engine that produces 30 percent less particulate pollution than the engine made by its main rival, Onez, now widely used in Marania; Ythex’s engine is well-suited for use in the thriving warehousing businesses in Marania, although it costs more than the Onez engine. The Maranian government plans to ban within the next two years the use of diesel engines with more than 80 percent of current diesel engine particulate emissions in Marania, and Onez will probably not be able to retool its engine to reduce emissions to reach this target. So if the ban is passed, the Ythex engine ought to sell well in Marania after that time.
Which of the following is an assumption on which the argument above depends?(E)
A. Marania’s warehousing and transshipment business buys more diesel engines of any size than other types of engines.
B. Ythex is likely to be able to reduce the cost of its small diesel engine within the next two years.
C. The Maranian government is generally favorable to anti-pollution regulations.
D. The government’s ban on high levels of pollution caused by diesel engines, if passed, will not be difficult to enforce.
E. The other manufacturers of small diesel engines in Marania, if there are any, have not produced an engine as popular and clean-running as Ythex’s new engine.
Situation Two companies, Ythex and Onez, produce diesel engines in Marania. Ythex has developed a small engine that produces less particulate pollution than the engine made by Onez, its main rival. The Maranian government will put a new maximum particulate-emission level in force within two years, but Onez will not be able to meet this target.
Reasoning What would have to be assumed for the argument to support the prediction that Ythex’s engine will sell well in two years when the new maximum particulate level is introducedl’To answer this, one might ask, for example: Will the maximum level be efficiently enforced? Will Ythex have any rivals other than Onez that will compete in the low-pollution diesel market?
A This tells us that there is a significant market for diesel engines, but this not an assumption that the reasoning depends on. The reasoning focuses only on the market for diesel engines and does not address the relative sizes of the market for diesel engines and that for non-diesel engines.
B If this is true, it provides additional support for the conclusion that Ythex’s engine will sell well in two years. However, it is not an assumption on which the reasoning relies.
C This information is peripheral to the reasoning and not an assumption on which the reasoning relies. Adding it to the information given would not make the reasoning more logically compelling.
D The ban might be quite difficult to enforce, but a more important issue is whether the ban will be effectively enforced (so the reasoning does have to assume that the ban would be at least somewhat effective). No assumption about the relative difficulty of enforcing the ban needs to be made for the reasoning to be logically compelling.
E Correct. Are there one or more diesel engines from other companies that will be able to compete effectively with Ythex’s engine when the ban is introduced? For the reasoning to be logically compelling, it needs to be assumed that the answer is no.
The correct answer is E.
13.In parts of South America, vitamin-A deficiency is a serious health problem, especially among children. In one region, agriculturists are attempting to improve nutrition by encouraging farmers to plant a new variety of sweet potato called SPK004 that is rich in beta-carotene, which the body converts into vitamin A. The plan has good chances of success, since sweet potato is a staple of the region’s diet and agriculture, and the varieties currently grown contain little beta-carotene.
Which of the following, if true, most strongly supports the prediction that the plan will succeed?(A)
A. The growing conditions required by the varieties of sweet potato currently cultivated in the region are conditions in which SPK004 can flourish.
B. The flesh of SPK004 differs from that of the currently cultivated sweet potatoes in color and texture, so traditional foods would look somewhat different when prepared from SPK004.
C. There are no other varieties of sweet potato that are significantly richer in beta-carotene than SPK004 is.
D. The varieties of sweet potato currently cultivated in the region contain some important nutrients that are lacking in SPK004.
E. There are other vegetables currently grown in the region that contain more beta-carotene than the currently cultivated varieties of sweet potato do.
解析：Evaluation of a Plan
Situation Agriculturists believe that if farmers in a particular South American region plant a new beta-carotene-rich variety of sweet potato, SPK004, the vitamin-A deficiency suffered in that region can be alleviated. Even though sweet potatoes are a staple of the region and the body can convert a sweet potato’s beta-carotene into vitamin A, the varieties currently grown there contain little beta-carotene.
Reasoning What would most support the success of the plan to improve nutrition by encouraging farmers to plant SPK004? What, that is, would make farmers respond positively to encouragement to plant SPK004? Farmers in the region would probably be inclined to substitute SPK004 for the varieties of sweet potato they currently grow if they could be assured that SPK004 would grow as well as those other varieties do. This would in turn most likely lead to SPK004 being substituted for current varieties of sweet potato in staple dishes, and thus to an improvement in nutrition in the region.
Correct. This statement properly identifies a factor that would support a prediction of the plan’s success.
If dishes made with SPK004 look different than traditional sweet potato dishes in the region do, people might be less likely to eat those dishes; in such a situation, the plan’s success would be less likely, rather than more likely.
It is SPK004’s beta-carotene content relative to the beta-carotene content of the sweet potatoes currently grown in the region that is relevant here, so it does not matter if there are other varieties of sweet potato that are richer in beta-carotene than SPK004 is.
This suggests that switching from currently grown sweet potatoes to SPK004 could negatively affect nutrition in the region; this undermines, rather than supports, the prediction that the plan to improve nutrition will succeed.
These other vegetables, despite their beta-carotene content being higher than that of the currently cultivated varieties of sweet potato, are clearly not sufficient to prevent a vitamin-A deficiency in the region. This information does nothing to support the prediction that encouraging farmers to plant SPK004 will help to meet those beta-carotene needs.
The correct answer is A.
14.Which of the following most logically completes the argument?
The last members of a now-extinct species of a European wild deer called the giant deer lived in Ireland about 16,000 years ago. Prehistoric cave paintings in France depict this animal as having a large hump on its back. Fossils of this animal, however, do not show any hump. Nevertheless, there is no reason to conclude that the cave paintings are therefore inaccurate in this regard, since_________.(C)
A. some prehistoric cave paintings in France also depict other animals as having a hump
B. fossils of the giant deer are much more common in Ireland than in France
C. animal humps are composed of fatty tissue, which does not fossilize
D. the cave paintings of the giant deer were painted well before 16,000 years ago
E. only one currently existing species of deer has any anatomical feature that even remotely resembles a hump
Situation Representations found in prehistoric cave paintings in France of the now-extinct giant deer species—the last members of which lived in Ireland about 16,000 years ago—depict the deer as having a hump on its back. Fossils of the deer, however, do not feature a hump.
Reasoning What point would most logically complete the argument? That is, what would show that the cave paintings are not inaccurate even though fossils of the giant deer show no hump? How could it be the case that the paintings show a hump while the fossils do not? One way in which this could be so is if the humps are not part of the fossils—that is, if there is some reason why a hump would not be preserved with the rest of an animal’s remains.
A We do not know whether these other cave paintings accurately depict the animals as having humps, so this provides no reason to think that the depictions of giant deer are accurate.
B Where giant deer fossils are found has no bearing on whether cave paintings of giant deer that show a hump on the animal’s back are inaccurate. It could be that this suggests that the painters responsible for the representations would not be very familiar with the species; if this were so, it would give some reason to conclude that the representations were inaccurate.
C Correct. This statement properly identifies a point that logically completes the argument. A hump would not be found as part of a giant deer’s fossilized remains if the humps were fatty tissue that would not be fossilized.
D That the cave paintings were painted well before 16,000 years ago shows that they were executed before the giant deer became extinct, but this does not help to explain the discrepancy between the paintings’ depiction of a hump on the deer’s back and the fossil record’s lack of such a hump. It could be that ever though the cave painters coexisted with the giant deer, they were not sufficiently familiar with them to depict them accurately.
E That currently existing species of deer lack humps, or even that one species does have a feature resembling a hump, has little bearing on whether cave paintings in France accurately depict the giant deer as having a hump.
The correct answer is C.
15.Super Express Shipping Company has implemented a new distribution system that can get almost every package to its destination the day after it is sent. The company worries that this more efficient system will result in lower sales of its premium next-day delivery service, because its two-day service will usually arrive the following day anyway. The company plans to encourage sales of its next-day service by intentionally delaying delivery of its two-day packages so that they will not be delivered the following day, even if the package arrives at its destination city in time for next-day delivery.
The company’s plan assumes that(A)
A. deliberate delay of packages will not affect the company’s image in a way that significantly reduces its ability to attract and retain customers
B. most people do not have a preference for either two-day or next-day delivery
C. if the plan is not implemented, the company would lose more money in lost sales of overnight deliveries than it would save with its new efficient distribution system
D. the overnight service is too expensive to be attractive to most customers currently
E. competing companies’ delivery services rarely deliver packages to their destination earlier than their promised time
解析：Evaluation of a Plan
Situation Super Express, a shipping company, is concerned that a new level of efficiency in its delivery process, resulting in next-day delivery even with guaranteed two-day delivery, might sabotage the company’s more expensive \
16.Cocoa grown organically on trees within the shade of the rain forest canopy commands a premium price. However, acquiring and maintaining the certification that allows the crop to be sold as organically grown is very time-consuming and laborious. Meanwhile, the price premium for the grower is about 30 percent, whereas cocoa trees grown in full sun using standard techniques can have twice the yield of organic, shade-grown trees. Financially, therefore, standard techniques are the better choice for the farmer.
Which of the following, if true, most seriously weakens the argument?(B)
A. Cocoa can be grown only in a climate that has the temperature and moisture characteristics of a tropical rain forest.
B. Cocoa trees grown using standard techniques require costly applications of fertilizer and pesticides, unlike shade-grown trees.
C. Although organically grown cocoa has long commanded a price premium over cocoa grown using standard techniques, its price has fluctuated considerably during that period.
D. Cocoa is not the only cash crop that can be raised on plots that leave the rain forest canopy overhead essentially intact.
E. Governments and international conservation organizations are working to streamline organic certification so as to relieve farmers of unnecessary work.
Situation Cocoa grown organically under the rain forest canopy can obtain a price premium of 30 percent for the grower. But the certification needed for the cocoa to be sold as organic is time-consuming and laborious. Since cocoa grown in full sun by standard (non-organic) techniques can have twice the yield, it is concluded that standard techniques are better financially for the farmer.
Reasoning Among the pieces of information presented, which one, assuming it is accurate, would most weaken the argument if added to the given information? Specific information about the costs associated with growing cocoa using standard techniques is lacking in the given information. For example, does use of the \
17.High levels of fertilizer and pesticides, needed when farmers try to produce high yields of the same crop year after year, pollute water supplies. Experts therefore urge farmers to diversify their crops and to rotate their plantings yearly.
To receive governmental price-support benefits for a crop, farmers must have produced that same crop for the past several years.
The statements above, if true, best support which of the following conclusions?(A)
A. The rules for governmental support of farm prices work against efforts to reduce water pollution.
B. The only solution to the problem of water pollution from fertilizers and pesticides is to take farmland out of production.
C. Farmers can continue to make a profit by rotating diverse crops, thus reducing costs for chemicals, but not by planting the same crop each year.
D. New farming techniques will be developed to make it possible for farmers to reduce the application of fertilizers and pesticides.
E. Governmental price supports for farm products are set at levels that are not high enough to allow farmers to get out of debt.
Situation Farmers are urged to rotate crops annually because the chemicals they must use when continuing to produce the same crops pollute water supplies. On the other hand, farmers may receive federal price-support benefits only if they have been producing the same crop for the past several years.
Reasoning What conclusion can be drawn from this information? Farmers wish to receive the price-support benefits offered by the government, so they grow the same crop for several years. In order to continue getting good yields, they use the high levels of chemicals necessary when the same crop is grown from year to year. The result is water pollution. The government’s rules for price-support benefits work against the efforts to reduce water pollution.
A Correct. This statement properly identifies the conclusion supported by the evidence.
B The experts cited in the passage believe that the rotation of crops is the solution, not the removal of farmland from production.
C The conclusion that farmers cannot make a profit by producing the same crop year after year is not justified by the information given in the premises. The information given suggests that this conclusion would actually be false, since these farmers would benefit by price-support measures for such a crop.
D No information in the passage supports a conclusion about farming techniques other than crop diversification and rotation, which are clearly existing farming techniques and not new or yet to be developed.
E This conclusion is unwarranted because there is no information in the two statements about the levels of the price supports and of the farmers’ debts.
The correct answer is A.
18.Ten years ago the number of taxpayers in Greenspace County was slightly greater than the number of registered voters. The number of taxpayers has doubled over the last ten years, while the number of registered voters has increased, but at a lower rate than has the number of taxpayers.
Which of the following must be true in Greenspace County if the statements above are true?(D)
A. The number of taxpayers is now smaller than the number of registered voters.
B. Everyone who is a registered voter is also a taxpayer.
C. The proportion of registered voters to taxpayers has increased over the last ten years.
D. The proportion of registered voters to taxpayers has decreased over the last ten years.
E. The proportion of registered voters to taxpayers has remained unchanged over the last ten years.
Situation Ten years ago a county had slightly more taxpayers than registered voters. Since then the number of taxpayers has doubled, while the number of registered voters has increased less.
Reasoning What can be deduced from the information about the changing numbers of taxpayers and registered voters?There were already slightly more taxpayers than registered voters ten years ago, but since then the number of taxpayers has increased more than proportionately to the number of registered voters. It follows that there must still be more taxpayers than registered voters, that the absolute number of taxpayers must have increased more than the absolute number of registered voters has, and that the ratio of taxpayers to registered voters must have increased.
A Since there were already more taxpayers than registered voters ten years ago, and since the number of taxpayers has increased more than the number of registered voters, there must still be more taxpayers than registered voters.
B Although there are more taxpayers than registered voters overall, there could still be many individual registered voters who are not taxpayers.
C Since the number of taxpayers has doubled while the number of registered voters has less than doubled, the proportion of registered voters to taxpayers must have decreased, not increased as this option claims
D Correct. Since the number of taxpayers has doubled while the number of registered voters has less than doubled, the proportion of registered voters to taxpayers must have decreased.
E Since the number of taxpayers has doubled while the number of registered voters has less than doubled, the proportion of registered voters to taxpayers must have decreased, not remained unchanged.
The correct answer is D.
19.From 1900 until the 1930s, pellagra, a disease later discovered to result from a deficiency of the vitamin niacin, was common among poor cotton farmers in the United States whose diet consisted mostly of corn, the least costly food they could buy. Corn does not contain niacin in usable form. Curiously, during the Depression of the early 1930s, when cotton’s price collapsed and cotton farmers’ income declined, the incidence of pellagra among those farmers also declined.
Which of the following, if true, most helps to explain the decline in the incidence of pellagra?(A)
A. When growing a cash crop could not generate adequate income, poor farmers in the United States responded by planting their land with vegetables and fruits for their own consumption.
B. People whose diets consist largely of corn often suffer from protein deficiency as well as niacin deficiency.
C. Until the discovery of pellagra’s link with niacin, it was widely believed that the disease was an infection that could be transmitted from person to person.
D. Effective treatment for pellagra became available once its link with niacin was established.
E. In parts of Mexico, where people subsisted on corn but pellagra was uncommon, corn was typically processed with alkaline substances, which make the niacin in the corn absorbable.
Situation The disease pellagra, which is due to a deficiency of the nutrient niacin, was common among poor cotton farmers in the United States during the early part of the 20th century, until the early 1930s. The diet of these farmers consisted mostly of the inexpensive grain corn, which lacked niacin in a form that can be absorbed by the body However, when the cotton price collapsed during the Great Depression in the early 1930s, the incidence of pellagra decreased among these farmers.
Reasoning What might explain the decline in incidence of pellagra among the cotton farmers during the Great Depression, despite the likelihood that the farmers would have experienced an increase in poverty? It may seem \
20.The interview is an essential part of a successful hiring program because, with it, job applicants who have personalities that are unsuited to the requirements of the job will be eliminated from consideration.
The argument above logically depends on which of the following assumptions?(C)
A. A hiring program will be successful if it includes interviews.
B. The interview is a more important part of a successful hiring program than is the development of a job description.
C. Interviewers can accurately identify applicants whose personalities are unsuited to the requirements of the job.
D. The only purpose of an interview is to evaluate whether job applicants’ personalities are suited to the requirements of the job.
E. The fit of job applicants’ personalities to the requirements of the job was once the most important factor in making hiring decisions.
Situation The interview is a necessary part of hiring because candidates with unsuitable personalities are eliminated from consideration.
Reasoning What is being assumed in this argument? The argument puts forth one reason that the interview is important: it eliminates candidates with unsuitable personalities. This presupposes that interviewers can, with a fair degree of accuracy, rule out those candidates whose personalities do not fit the needs of the job.
A The argument does not go so far as to say that interviews guarantee a successful hiring program.
B The argument does not prioritize the parts of a hiring program.
C Correct. This statement properly identifies the assumption underlying the argument.
D The argument gives one reason that the interview is important, but it does not say it is the only reason.
E This concerns past practices in hiring, and is irrelevant to the argument.
The correct answer is C.
21.Many leadership theories have provided evidence that leaders affect group success rather than the success of particular individuals. So it is irrelevant to analyze the effects of supervisor traits on the attitudes of individuals whom they supervise. Instead, assessment of leadership effectiveness should occur only at the group level.
Which of the following would it be most useful to establish in order to evaluate the argument?(E)
A. Whether supervisors’ documentation of individual supervisees’ attitudes toward them is usually accurate
B. Whether it is possible to assess individual supervisees’ attitudes toward their supervisors without thereby changing those attitudes
C. Whether any of the leadership theories in question hold that leaders should assess other leaders’ attitudes
D. Whether some types of groups do not need supervision in order to be successful in their endeavors
E. Whether individuals’ attitudes toward supervisors affect group success
Situation Many leadership theories have provided evidence that leaders affect the success of groups but not of individuals.
Reasoning What would be most helpful to know in order to evaluate how well the stated fact supports the conclusion that leadership effectiveness should be assessed only at the group level without considering supervisors’ influence on the attitudes of the individuals they supervise? Even if leaders do not affect the success of the individuals they lead, they might still affect those individuals’ attitudes. And those attitudes in turn might affect group success. If so, the argument would be weak. So any evidence about the existence or strength of these possible effects in the relationship between supervisors and their supervisees would be helpful in evaluating the argument.
A How accurately supervisors document their supervisees’ attitudes is not clearly relevant to how much the supervisors affect those attitudes, nor to how much the attitudes affect group success.
B Even if assessing supervisees’ attitudes would in itself change those attitudes, the person doing the assessment might be able to predict this change and take it into account. Thus, considering individual supervisees’ attitudes might still be worthwhile.
C The argument is not about interactions among leaders, but rather about interactions between supervisors and supervisees.
D The argument is not about groups without supervisors, or whether certain groups might be effective without a supervisor, but rather about how to assess the effectiveness of supervisors in groups that do have them.
E Correct. As explained above, if individual supervisees’ attitudes affect group success, the argument would be weak. And probably individual supervisees’ attitudes toward their supervisors are influenced by those supervisors. So knowing whether individual attitudes toward supervisors affect group success would be helpful in evaluating the argument
The correct answer is E.
22.A major health insurance company in Lagolia pays for special procedures prescribed by physicians only if the procedure is first approved as \(C)
A. Patients often register dissatisfaction with physicians who prescribe nothing for their ailments.
B. Physicians often prescribe special procedures that are helpful but not altogether necessary for the health of the patient.
C. The review process is expensive and practically always results in approval of the prescribed procedure.
D. The company’s review process does not interfere with the prerogative of physicians, in cases where more than one effective procedure is available, to select the one they personally prefer.
E. The number of members of the company-appointed review panel who review a given procedure depends on the cost of the procedure.
解析：Evaluation of a Plan
Situation In order to cut costs, a major health insurance company is abandoning a rule stating that it will pay for special procedures only if the procedure is approved as medically necessary by a review panel.
Reasoning What piece of information would most help to justify the company’s decision? For the company to save money, it would need to be in some way cutting its costs by abandoning the rule. Under what circumstances might the rule cost, rather than save, the company money? The panel itself might be expensive to convene, for example. Further, the cost savings achieved by the panel might be minimal if the panel did not deny significant numbers of procedures.
A This suggests that patients might be pressuring their physicians to prescribe certain unnecessary procedures for their ailments, which in turn suggests that the panel is reviewing these procedures and denying them. But if so, then the panel is probably saving the insurance company money, so abandoning the panel’s review would not reduce the company’s costs.
B This suggests that certain procedures that are being prescribed by physicians are not medically necessary, which in turn suggests that the panel reviewing these procedures may be denying them. If this is the case, then the panel is probably saving the insurance company a significant amount of money, so abandoning the panel’s review may well increase rather than decrease the company’s costs.
C Correct. This statement properly identifies information that would help to justify the company’s decis on.
D Even if the panel does not interfere with physicians’ choices when more than one medically effective procedure is available, the panel may still be denying pay for many procedures that are not medically necessary. In such cases the panel may be saving the insurance company money, and abandoning the review process would not reduce the company’s costs.
E This suggests that the more expensive the procedure under review, the more expensive the panel itself’s. Even so, if the panel denies payment for very expensive procedures, it may nonetheless save the company significantly more than the company has to pay to convene the panel, so abandoning the review process would not reduce the company’s costs.
The correct answer is C.
23.Automobile ownership was rare in Sabresia as recently as 30 years ago, but with continuing growth of personal income there, automobile ownership has become steadily more common. Consequently, there are now far more automobiles on Sabresia’s roads than there were 30 years ago, and the annual number of automobile accidents has increased significantly. Yet the annual number of deaths and injuries resulting from automobile accidents has not increased significantly.
Which of the following, if true, most helps to explain why deaths and injuries resulting from automobile accidents have not increased significantly?(B)
A. Virtually all of the improvements in Sabresia’s roads that were required to accommodate increased traffic were completed more than ten years ago.
B. With more and more people owning cars, the average number of passengers in a car on the road has dropped dramatically.
C. The increases in traffic volume have been most dramatic on Sabresia’s highways, where speeds are well above those of other roads.
D. Because of a vigorous market in used cars, the average age of cars on the road has actually increased throughout the years of steady growth in automobile ownership.
E. Automobile ownership is still much less common in Sabresia than it is in other countries.
Situation Many more cars are on Sabresia’s roads than 30 years ago; and there are also many more car accidents. Yet the annual number of deaths and injuries resulting from car accidents has not increased much, which is quite puzzling.
Reasoning What factor could help explain the puzzling fact that the increase in car accidents was not reflected in a similar increase in deaths and injuries from car accidents? One (but perhaps unlikely) possibility is that a significantly greater proportion of the recent annual number of car accidents consisted of merely minor accidents, unlike 30 years ago. Another possibility is that cars are currently much better engineered for driver and passenger safety than 30 years ago. Yet a third possibility is that the total number of people traveling by car—passengers and drivers—has not increased significantly despite the large increase in the number of cars. This would mean that the average occupancy of a car has greatly decreased; so, even though the number of car accidents has significantly increased, the average number of people per car involved in an accident would have decreased significantly. On average, this would mean significantly fewer deaths and injuries per accident.
A This throws little light on the central puzzle: why the current number of car accidents is significantly higher than 30 years ago, while the number of deaths and injuries in car accidents is not. The fact that there has been a significant increase in car accidents suggests that the roads were not made as safe as they could have been, and this just deepens the puzzle about the lack of a significant increase in deaths and injuries.
B Correct. This implies that the average number of passengers per car accident is significantly less, and this helps explain why the total number of deaths and injuries has not increased significantly.
C This information does not help explain the mismatch between increased accident numbers and relatively stable death-and-injury numbers. High-speed car accidents would likely have caused more fatalities, on average, than other car accidents; so, given that the increase in traffic volume has been greatest on Sabresia’s high-speed roads, one would expect a significant increase in the number of accidents, and consequently in the number of deaths and injuries. But this expectation has not been fulfilled.
D This does not help explain the surprisingly stable death-and-injury numbers in contrast with the
significantly increased number of car accidents. The increase in average age of cars on the road might contribute to the increased number of accidents if older cars are more likely to be dangerously defective than newer ones.
E The central puzzle already described involves no comparisons between Sabresia and other countries, so this information is irrelevant to explaining the puzzling discrepancy.
The correct answer is B.
24.To evaluate a plan to save money on office-space expenditures by having its employees work at home, XYZ Company asked volunteers from its staff to try the arrangement for six months. During this period, the productivity of these employees was as high as or higher than before.
Which of the following, if true, would argue most strongly against deciding, on the basis of the trial results, to implement the company’s plan?(A)
A. The employees who agreed to participate in the test of the plan were among the company’s most self-motivated and independent workers.
B. The savings that would accrue from reduced office-space expenditures alone would be sufficient to justify the arrangement for the company, apart from any productivity increases.
C. Other companies that have achieved successful results from work-at-home plans have workforces that are substantially larger than that of XYZ.
D. The volunteers who worked at home were able to communicate with other employees as necessary for performing the work.
E. Minor changes in the way office work is organized at XYZ would yield increases in employee productivity similar to those achieved in the trial.
解析：Evaluation of a Plan
Situation To save money on office space expenditures, a company considers having employees work at home. A six-month trial with employees who have volunteered to test the plan shows their productivity to be as high as or higher than before.
Reasoning Why would the trial results NOT provide a good reason to implement the plan? Generalizing from a small sample to the group depends on having a sample that is representative. In this case, the employees who participated in the trial are not representative of all employees. The employees who volunteered for the trial may be the type of employees who would be most likely to work successfully at home. It would not be wise to base a generalization about all employees on this sample.
A Correct. This statement properly identifies a flaw in the trial that is the basis for the plan.
B This statement supports the implementation of the plan. Moreover, it is not based on the trial results, so it does not answer the question.
C The passage gives no information about how company size might affect the implementation of the plan or the reliability of the trial results.
D If anything, this would tend to support the plan.
E The goal of the plan is to save money on office space, not to increase productivity, so an alternative plan to increase productivity is irrelevant.
The correct answer is A.
25.A child learning to play the piano will not succeed unless the child has an instrument at home on which to practice. However, good-quality pianos, whether new or secondhand, are costly. Buying one is justified only if the child has the necessary talent and perseverance, which is precisely what one cannot know in advance. Consequently, parents should buy an inexpensive secondhand instrument at first and upgrade if and when the child’s ability and inclination are proven.
Which of the following, if true, casts the most serious doubt on the course of action recommended for parents?(A)
A. Learners, particularly those with genuine musical talent, are apt to lose interest in the instrument if they have to play on a piano that fails to produce a pleasing sound.
B. Reputable piano teachers do not accept children as pupils unless they know that the children can practice on a piano at home.
C. Ideally, the piano on which a child practices at home should be located in a room away from family activities going on at the same time.
D. Very young beginners often make remarkable progress at playing the piano at first, but then appear to stand still for a considerable period of time.
E. In some parents, spending increasing amounts of money on having their children learn to play the piano produces increasing anxiety to hear immediate results.
解析：Evaluation of a Plan
Situation Children learning the piano need to have a piano on which to practice at home. Purchasing a high-quality piano is costly, and justified only if the child has talent and will persevere, which is hard to predict at an early stage. Parents should make do with a secondhand piano until the child’s ability and inclination are proven.
Reasoning Which of the statements given would cast the most serious doubt on the recommendation given to parents? Suppose that a child, because possessed of very high musical talent, is especially sensitive to imprecisions in tuning or imperfections of tone in a secondhand, less expensive piano (presumably Mozart would have been so!). This could, over time, make the child less interested in using the piano—especially if the child had the opportunity to hear music on far superior pianos. The result could be total loss of interest in learning to play the piano.
A Correct. This, if true, would be a good reason to provide the child with the chance to practice regularly on a superior piano.
B The issue is whether it would be best to provide the child with a superior piano at home, not whether it would be important to provide some piano at home.
C This is irrelevant to the point at issue, which concerns how high a quality of piano should parents provide at home if they desire optimal development of the child’s potential for piano musicianship.
D Fluctuations in the pace of learning the piano are possible, but not relevant to the central question raised about the quality of the piano to be provided.
E Investing so much in a piano, to the extent that doing so causes financial and psychological stress, might not be beneficial overall. However, if buying a new piano and buying a used piano are equally feasible financially for a given family, the question concerns which option would most achieve the objective of optimally developing the child’s potential for piano musicianship.
The correct answer is A.