削弱题-CR-PREP:第21-30题 练习册详情

1

Tiger sharks are common in the waters surrounding Tenare Island. Usually tiger sharks feed on smaller sharks, but sometimes they have attacked tourists swimming and surfing at Tenare's beaches. This has hurt Tenare's tourism industry, which is second only to its fishing industry in annual revenues. In order to help the economy, therefore, the mayor of the island has proposed an ongoing program to kill any tiger sharks within a mile of the beaches.

Which of the following, if true, most strongly calls into question the likelihood that implementation of the mayor's proposal will have the desired consequence?

• Even if not all the tiger sharks that come close to the beaches are killed, the existence of the program would reassure tourists.
• Business owners who depend on tourism are willing to pay most of the cost of implementing the program.
• Tourists come to Tenare Island for its beaches, even though the island features a number of other tourist attractions.
• The small sharks on which tiger sharks prey feed on fish that are commercially important to the island's fisheries.
• Not all tourists who come to Tenare Island enjoy swimming or surfing.

9981人做过此题 平均耗时为10min46s 平均正确率为 51%

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2

Economist: On average, the emergency treatment for an elderly person for injuries resulting from a fall costs $11,000. A new therapeutic program can significantly reduce an elderly person's chances of falling. Though obviously desirable for many reasons, this treatment program will cost $12,500 and thus cannot be justified.

Which of the following, if true, most seriously undermines the conclusion of the argument?

• Among elderly people who had followed the program for only a few months, the number of serious falls reported was higher than it was for people who had followed the program for its recommended minimum length of one year.
• Falls resulting in serious injuries are less common among elderly people living in nursing homes than they are among elderly people who live alone at home.
• A frequent result of injuries sustained in falls is long-term pain, medication for which is not counted among the average per-person costs of emergency treatment for elderly people's injuries from such falls.
• The new therapeutic program focuses on therapies other than medication, since overmedication can cause disorientation and hence increase the likelihood that an elderly person will have a serious fall.
• A significant portion of the cost of the new therapeutic program is represented by regular visits by health care professionals, the costs of which tend to increase more rapidly than do those of other elements of the program.

9971人做过此题 平均耗时为8min1s 平均正确率为 60%

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3

Although fullerenes--spherical molecules made entirely of carbon--were first found in the laboratory, they have since been found in nature, formed in fissures of the rare mineral shungite. Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, this discovery should give geologists a test case for evaluating hypotheses about the state of the Earth's crust at the time these naturally occurring fullerenes were formed.

Which of the following, if true, most seriously undermines the argument?

• Confirming that the shungite genuinely contained fullerenes took careful experimentation.
• Some fullerenes have also been found on the remains of a small meteorite that collided with a spacecraft.
• The mineral shungite itself contains large amounts of carbon, from which the fullerenes apparently formed.
• The naturally occurring fullerenes are arranged in a previously unknown crystalline structure.
• Shungite itself is formed only under distinctive conditions.

9995人做过此题 平均耗时为7min51s 平均正确率为 45%

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4

Early in the twentieth century, Lake Konfa became very polluted. Recently fish populations have recovered as release of industrial pollutants has declined and the lake's waters have become cleaner. Fears are now being voiced that the planned construction of an oil pipeline across the lake's bottom might revive pollution and cause the fish population to decline again. However, a technology for preventing leaks is being installed. Therefore, provided this technology is effective, the fears are groundless.

Which of the following, if true, most seriously weakens the argument?

• The pipeline's construction will disturb sediments at the bottom of the lake, dispersing into the water toxic pollutants that have settled there.
• Changes in land use and drainage patterns around the lake mean that the lake's waters are increasingly likely to be affected by agricultural runoff.
• The leak-preventing technology has been in use for several years without any pipeline in which it is installed developing serious leaks.
• A major leak of oil from the pipeline would harm not only the lake's fish but also populations of other aquatic animals and plants.
• Since the beginning of the twentieth century, non-native species of fish have been introduced into the lake and now make up a considerable proportion of its overall fish population.

6405人做过此题 平均耗时为3min30s 平均正确率为 48%

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5

Trancorp currently transports all its goods to Burland Island by truck. The only bridge over the channel separating Burland from the mainland is congested, and trucks typically spend hours in traffic. Trains can reach the channel more quickly than trucks, and freight cars can be transported to Burland by barges that typically cross the channel in an hour. Therefore, to reduce shipping time, Trancorp plans to switch to trains and barges to transport goods to Burland.

Which of the following, if true, casts most serious doubt on whether Trancorp's plan will succeed?

• It does not cost significantly more to transport goods to Burland by truck than it does to transport goods by train and barge.
• The number of cars traveling over the bridge into Burland is likely to increase slightly over the next two years.
• Because there has been so much traffic on the roads leading to the bridge between Burland and the mainland, these roads are in extremely poor condition.
• Barges that arrive at Burland typically wait several hours for their turn to be unloaded.
• Most trucks transporting goods into Burland return to the mainland empty.

3816人做过此题 平均耗时为1min53s 平均正确率为 92%

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6

Escalating worldwide demand for corn is expected to cause the market price of corn to rise sharply and remain high. Although corn is extensively used as feed for livestock, livestock feed accounts for only a small fraction of the retail price of meat. Therefore, the increase in corn prices is very unlikely to produce any comparable long-term increase in the retail price of meat.

Which of the following, if true, most seriously weakens the argument?

• The cost of shipping and handling meat has also risen sharply.
• Livestock producers who currently use corn to feed their livestock have the option of switching to other kinds of feed.
• The rising cost of feed is leading some livestock producers to leave the business, thereby reducing the future supply of meat.
• Worldwide demand for grains other than corn has also increased.
• The price of corn affects the retail price of a variety of other food products more than it affects the price of meat.

3901人做过此题 平均耗时为2min12s 平均正确率为 83%

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7

Editor: Articles in Gardening Magazine often spur sales of the plants they describe, particularly among people new to gardening. Accordingly, we will no longer publish articles or accept advertisements praising the beauty of rare wildflowers. Most such plants sold to gardeners have been difficult to propagate under cultivation, so plant sellers often collect them in the wild. Our new policy is part of our efforts to halt this yearly plundering of our native plant populations.

Which of the following, if true, casts the most doubt on the wisdom of the magazine's new policy as a way of pursuing the intended effect?

• When people new to gardening buy plants, they often fail to take adequate care of the plants that they buy and become discouraged from buying those varieties again.
• Plant sellers who sell rare wildflowers have no reasonably inexpensive alternative way to offer their wares directly to new gardeners.
• The demand for rare wildflowers rarely exceeds the number of such plants that can be collected in the wild by plant sellers.
• The propagation of rare wildflowers often depends on the plants' interaction with other organisms in their environment, such as plants that create suitable soil conditions or insects and birds that disperse seeds.
• Revenues from sales of plants collected in the wild are supporting the discovery of new low-cost techniques enabling rare wildflowers to be readily propagated in nurseries.

4735人做过此题 平均耗时为5min27s 平均正确率为 43%

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8

X: In order to reduce the amount of plastic in landfills, legislatures should impose a ban on the use of plastics for packaging goods.

Y: Impossible! Plastic packaging is necessary for public safety. Consumers will lose all of the safety features that plastic offers, chiefly tamper-resistant closures and shatterproof bottles.

Which of the following best describes the weak point in Y's response to X's proposal?

• Y ignores the possibility that packaging goods in materials other than plastic might provide the same safety features that packaging in plastic offers.
• The economic disadvantages of using plastics as a means of packaging goods are not taken into consideration.
• Y attempts to shift the blame for the large amount of plastic in landfills from the users of plastic packaging to the legislators.
• Y does not consider the concern of some manufacturers that safety features spoil package appearances.
• Y wrongly assumes that X defends the interests of the manufacturers rather than the interests of the consumers.

4529人做过此题 平均耗时为3min26s 平均正确率为 54%

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9

Many people suffer an allergic reaction to sulfites, including those that are commonly added to wine as preservatives. However, since there are several winemakers producing wine to which no sulfites are added, those who would like to drink wine but are allergic to sulfites can drink these wines without risking an allergic reaction to sulfites.

Which of the following, if true, most seriously weakens the argument?

• Sulfites occur naturally in most wine.
• The sulfites that can produce an allergic reaction are also commonly found in beverages other than wine.
• Wines without added sulfites tend to be at least moderately expensive.
• Apart from sulfites, there are other substances commonly present in wine that can trigger allergic reactions.
• Wine without added sulfites sometimes becomes undrinkable even before the wine is sold to consumers.

9989人做过此题 平均耗时为9min7s 平均正确率为 51%

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10

The country of Baurisia has, until now, been self-sufficient in both grain and meat. However, with growing prosperity in Baurisia has come a steadily increasing per capita consumption of meat, and it takes several pounds of grain to produce one pound of meat. Therefore, since per capita income in Baurisia is almost certain to rise further but increases in domestic grain production are highly unlikely, Baurisia is soon likely to become an importer of grain.

Which of the following, if true, most seriously weakens the argument?

• When people increase their consumption of meat, they also tend to increase their consumption of grain.
• The per capita consumption of meat in Baurisia is roughly the same across all income levels.
• Per capita consumption of meat has not increased substantially in recent years in those countries from which Baurisia is likely to import meat.
• It is more economical for Baurisians to import meat than grain.
• During Baurisia's years of growing prosperity, the country's population has remained relatively stable.

262人做过此题 平均耗时为5min26s 平均正确率为 40%

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