07年GMAT最新逻辑推理试题训练二十一(B)

9.  Passengers must exit airplanes swiftly after accidents, since gases released following accidents are toxic to humans and often explode soon after being released. In order to prevent passenger deaths from gas inhalation, safety officials recommend that passengers be provided with smoke hoods that prevent inhalation of the gases.
    Which of the following, if true, constitutes the strongest reason not to require implementation of the safety officials’ recommendation?
(A) Test evacuations showed that putting on the smoke hoods added considerably to the overall time it took passengers to leave the cabin.
(B) Some airlines are unwilling to buy the smoke hoods because they consider them to be prohibitively expensive.
(C) Although the smoke hoods protect passengers from the toxic gases, they can do nothing to prevent the gases from igniting.
(D) Some experienced flyers fail to pay attention to the safety instructions given on every commercial flight before takeoff
(E) In many airplane accidents, passengers who were able to reach emergency exits were overcome by toxic gases before they could exit the airplane.
10. In 1960, 10 percent of every dollar paid in automobile insurance premiums went to pay costs arising from injuries incurred in car accidents. In 1990, 50 percent of every dollar paid in automobile insurance premiums went toward such costs, despite the fact that cars were much safer in 1990 than in 1960.
    Which of the following, if true, best explains the discrepancy outlined above?
(A) There were fewer accidents in 1990 than in 1960.
(B) On average, people drove more slowly in 1990 than in 1960.
(C) Cars grew increasingly more expensive to repair over the period in question.
(D) The price of insurance increased more rapidly than the rate of inflation between 1960 and 1990
(E) Health-care costs rose sharply between 1960 and 1990.
11. Caterpillars of all species produce an identical hormone called “juvenile hormone” that maintains feeding behavior. Only when a caterpillar has grown to the right size for pupation to take place does a special enzyme halt the production of juvenile hormone. This enzyme can be synthesized and will, on being ingested by immature caterpillars, kill them by stopping them from feeding.
    Which of the following, if true, most strongly supports the view that it would not be advisable to try to eradicate agricultural pests that go through a caterpillar stage by spraying croplands with the enzyme mentioned above?
(A) Most species of caterpillar are subject to some natural predation.
(B) Many agricultural pests do not go through a caterpillar stage.
(C) Many agriculturally beneficial insects go through a caterpillar stage.
(D) Since caterpillars of different species emerge at different times, several sprayings would be necessary
(E) Although the enzyme has been synthesized in the laboratory, no large-scale production facilities exist as yet.
12. Although aspirin has been proven to eliminate moderate fever associated with some illnesses, many doctors no longer routinely recommend its use for this purpose. A moderate fever stimulates the activity of the body’s disease-fighting white blood cells and also inhibits the growth of many strains of disease-causing bacteria.
    If the statements above are true, which of the following conclusions is most strongly supported by them?
(A) Aspirin, an effective painkiller, alleviates the pain and discomfort of many illnesses.
(B) Aspirin can prolong a patient’s illness by eliminating moderate fever helpful in fighting some diseases.
(C) Aspirin inhibits the growth of white blood cells, which are necessary for fighting some illnesses.
(D) The more white blood cells a patient’s body produces, the less severe the patient’s illness will be
(E) The focus of modern medicine is on inhibiting the growth of disease-causing bacteria within the body.
13. Because postage rates are rising, Home Decorator magazine plans to maximize its profits by reducing by one half the number of issues it publishes each year. The quality of articles, the number of articles published per year, and the subscription price will not change. Market research shows that neither subscribers nor advertisers will be lost if the magazine’s plan is instituted.
    Which of the following, if true, provides the strongest evidence that the magazine’s profits are likely to decline if the plan is instituted?
(A) With the new postage rates, a typical issue under the proposed plan would cost about one-third more to mail than a typical current issue would.
(B) The majority of the magazine’s subscribers are less concerned about a possible reduction in the quantity of the magazine’s articles than about a possible loss of the current high quality of its articles.
(C) Many of the magazine’s long-time subscribers would continue their subscriptions even if the subscription price were increased.
(D) Most of the advertisers that purchase advertising space in the magazine will continue to spend the same amount on advertising per issue as they have in the past
(E) Production costs for the magazine are expected to remain stable.
14. A study of marital relationships in which one partner’s sleeping and waking cycles differ from those of the other partner reveals that such couples share fewer activities with each other and have more violent arguments than do couples in a relationship in which both partners follow the same sleeping and waking patterns. Thus, mismatched sleeping and waking cycles can seriously jeopardize a marriage.
    Which of the following, if true, most seriously weakens the argument above?
(A) Married couples in which both spouses follow the same sleeping and waking patterns also occasionally have arguments than can jeopardize the couple’s marriage.
(B) The sleeping and waking cycles of individuals tend to vary from season to season.
(C) The individuals who have sleeping and waking cycles that differ significantly from those of their spouses tend to argue little with colleagues at work.
(D) People in unhappy marriages have been found to express hostility by adopting a different sleeping and waking cycle from that of their spouses
(E) According to a recent study, most people’s sleeping and waking cycles can be controlled and modified easily.
Questions 15-16 are based on the following.
    Roland: The alarming fact is that 90 percent of the people in this country now report that they know someone who is unemployed.
Sharon: But a normal, moderate level of unemployment is 5 percent, with 1 out of 20 workers unemployed. So at any given time if a person knows approximately 50 workers, 1 or more will very likely be unemployed.
15. Sharon’s argument is structured to lead to which of the following as a conclusion?
(A) The fact that 90% of the people know someone who is unemployed is not an indication that unemployment is abnormally high.
(B) The current level of unemployment is not moderate.
(C) If at least 5% of workers are unemployed, the result of questioning a representative group of people cannot be the percentage Roland cites.
(D) It is unlikely that the people whose statements Roland cites are giving accurate reports
(E) If an unemployment figure is given as a certain percent, the actual percentage of those without jobs is even higher.
16. Sharon’s argument relies on the assumption that
(A) normal levels of unemployment are rarely exceeded
(B) unemployment is not normally concentrated in geographically isolated segments of the population
(C) the number of people who each know someone who is unemployed is always higher than 90% of the population
(D) Roland is not consciously distorting the statistics he presents
(E) knowledge that a personal acquaintance is unemployed generates more fear of losing one’s job than does knowledge of unemployment statistics

参考答案:
1-5:  (E)(C)(A)(B)(A)
6-10: (B)(E)(B)(A)(E)
11-16:(C)(B)(D)(D)(A)(B)
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