GMAT复习资料——逻辑重点题难题集（一）

kuaijizu

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?
(A) 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.
(B) 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.
(C) 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.
(D) 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.
(E) 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.
答案为C。根据题意，正确答案一定是从cost角度来说明该program其实是justified.

kuaijizu

In a study conducted in Pennsylvania, servers in various restaurants wrote “Thank you” on randomly selected bills before presenting the bills to their customers.  Tips on these bills were an average of three percentage points higher than tips on bills without the message.  Therefore, if servers in Pennsylvania regularly wrote “Thank you” on restaurant bills, their average income from tips would be significantly higher than it otherwise would have been.
Which of the following is an assumption on which the argument relies?
A.        The “Thank you” messages would have the same impact on regular patrons of a restaurant as they would on occasional patrons of the same restaurant.
B.        Regularly seeing “Thank you” written on their bills would not lead restaurant patrons to revert to their earlier tipping habits.
C.        The written “Thank you” reminds restaurant patrons that tips constitute a significant part of the income of many food servers.
D.        The rate at which people tip food servers in Pennsylvania does not vary with how expensive a restaurant is.
E.        Virtually all patrons of the Pennsylvania restaurants in the study who were given a bill with “Thank you” written on it left a larger tip than they otherwise would have.
答案为B。A项为干扰项。GMAC经常把这种貌似正确的干扰项放在正确选项之前，你在做题时一定要小心，别大意。

kuaijizu

For most people, the left half of the brain controls linguistic capabilities, but some people have their language centers in the right half. When a language center of the brains is damaged, for example, by a stroke, linguistic capabilities are impaired in some way. Therefore, people who have suffered a serious stroke on the left side of the brain without suffering any such impairment must have their language centers in the right half.
Which of the following is an assumption on which the reasoning in the argument above depends?
A.        No part of a person’s brain that is damaged by a stroke never recovers
B.        Impairment of linguistic capabilities does not occur in people who have not suffered any damage to any language center of the brain.
C.        Strokes tend to impair linguistic capabilities more severely than does any other cause of damage to language centers in the brain.
D.        If there are language centers on the left side of the brain, any serious stroke affecting that side of the brain damages at least one of them.
E.        It is impossible to determine which side of the brain contains a person’s language centers if the person has not suffered damage to either side of the brain.
答案为D。D选项说的是左侧大脑受伤的人，故与原文结论一致；B选项说的是大脑没受伤的人，故与原文结论无关。

kuaijizu

The chemical adenosine is released by brain cells when those cells are active. Adenosine then binds to more and more sites on cells in certain areas of the brain, as the total amount released gradually increases during wakefulness. During sleep, the number of sites to which adenosine is bound decreases. Some researchers have hypothesized that it is the cumulative binding of adenosine to a large number of sites that causes the onset of sleep.
Which of the following, if true, provides the most support for the researchers’ hypothesis?
A.        Even after long periods of sleep when adenosine is at its lowest concentration in the brain, the number of brain cells bound with adenosine remains very large.
B.        Caffeine, which has the effect of making people remain wakeful, is known to interfere with the binding of adenosine to sites on brain cells.
C.        Besides binding to sites in the brain, adenosine is known to be involved in biochemical reactions throughout the body.
D.        Some areas of the brain that are relatively inactive nonetheless release some adenosine.
E.        Stress resulting from a dangerous situation can preserve wakefulness even when brain levels of bound adenosine are high.
答案为B。本题的难点在于看懂并理解文章前三句话所表达的意思。D选项包含some，在加强题中不太可能正确。

kuaijizu

On the whole, scientists do their most creative work before age forty, a tendency that has been taken to show that aging carries with it a loss of creative capacity.  An alternative explanation is that by age forty most scientists have worked in their field for fifteen or more years and that by then they have exhausted the opportunity for creative work in that field.  Supporting this explanation is the finding that ______.
A.        the average age of recipients of scientific research grants is significantly greater than forty
B.        a disproportionately large number of the scientists who produce highly creative work beyond age forty entered their field at an older age than is common
C.        many scientists temper their own expectations of what they can achieve in their research work by their belief that their creativity will decline as they age
D.        scientists who are older than forty tend to find more satisfaction in other activities, such as teaching and mentoring, than they do in pursuing their own research
E.        there is a similar diminution of creativity with age in nonscientific fields, such as poetry and musical composition
答案为B。注意原文让你加强的其实就是An alternative explanation这句话。B选项很复杂故很可能正确。

kuaijizu

During the month of May, crabs arrive on Delaware’s beaches to lay eggs.  Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds.  Delaware’s crab population has declined recently.  This decline, however, poses no serious threat to the migrating shorebird populations:  by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.
Which of the following, if true, most seriously weakens the argument?
A.        No other food available to the birds on Delaware’s beaches is as nutritious and accessible as are crab eggs.
B.        The decline in the number of crabs on Delaware’s beaches is due to the harvesting of crabs by humans.
C.        There are more crabs on Delaware’s beaches than in any other area that the migrating birds pass through.
D.        The crabs do not conceal their eggs.
E.        The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.
答案为E。关键是理解原文Certain shorebird这句话——永远记住逻辑题的核心就是用原文前面内容回答后面问题。

kuaijizu

Microscopic plants called algae grow inside the top layer of sea ice in the Antarctic if enough sunlight reaches that layer of ice and enough seawater, which contains nutrients, reaches that layer after splashing onto the surface.  Even though moderate snow cover reduces the sunlight that filters into the top layer, sea ice with moderate snow cover typically contains even more algae in the top layer than does sea ice with less snow cover.
Which of the following, if true, most helps to explain the apparent discrepancy?
(A) As the weight of accumulated snow forces ice lower in the water, more seawater splashes onto the surface and seeps through the snow.
(B) Seawater in the Antarctic often contains higher concentrations of nutrients than does seawater in more temperate regions.
(C) As the air temperature around sea ice decreases during the winter, the likelihood decreases that snow will fall and thus add to any existing snow cover.
(D) The nutrients on which algae rely are common in seawater throughout the Antarctic.
(E) More sunlight filters through a layer of ice than through an equally thick layer of snow.
答案为A。正确解决本题的关键就是理解文章第一句话——永远记住逻辑题的核心就是用原文前面内容回答后面问题。

kuaijizu

In Kantovia, physicians’ income comes from insurance companies, which require physicians to document their decisions in treating patients and to justify deviations from the companies’ treatment guidelines. Ten years ago physicians were allowed more discretion. Most physicians believe that the companies’ requirements now prevent them from spending enough time with patients. Yet the average amount of time a patient spends with a physician during an office visit has actually increased somewhat over the last ten years.
Which of the following, if true, most helps to resolve the apparent discrepancy between physicians’ perceptions and the change in the actual time spent?
A.        Patients are more likely to be in a hurry nowadays and are less willing to wait a long time to see their physician.
B.        Physicians today typically have a wider range of options in diagnosis and treatment to consider with the patient before prescribing.
C.        Physicians are increasingly likely to work in group practices, sharing the responsibility of night and weekend work.
D.        Most patients would rather trust their physicians than their insurance companies to make decisions about their treatment.
E.        Since the insurance companies pay physicians a set amount for each office visit, it is to physicians’ financial advantage to see as many patients as possible.
答案为B。正确解决本题的关键就是理解文章第一句话——永远记住逻辑题的核心就是用原文前面内容回答后面问题。

kuaijizu

In Kravonia, the average salary for jobs requiring a college degree has always been higher than the average salary for jobs that do not require a degree. Current enrollments in Kravonia’s colleges indicate that over the next four years the percentage of the Kravonian workforce with college degree will increase dramatically. Therefore, the average salary for all workers in Kravonia is likely to increase over the next four years.
Which of the following is an assumption on which the argument depends?
A. Kravonians with more than one college degree earn more, on average, than do Kravonians with only one college degree.
B. The percentage of Kravonians who attend college in order to earn higher salaries is higher now than it was several years ago.
C. The higher average salary for jobs requiring a college degree is not due largely to a scarcity among the Kravonian workforce of people with a college degree.
D. The average salary in Kravonia for jobs that do not require a college degree will not increase over the next four years.
E. Few members of the Kravonian workforce earned their degrees in other countries.
答案为C。本题考查了一个最简单也是最常考的经济学常识——“物以稀为贵”（供求关系决定价格）

kuaijizu

Boreal owls range over a much larger area than do other owls of similar size. The reason for this behavior is that the small mammals on which owls feed are especially scarce in the forests where boreal owls live, and the relative scarcity of prey requires the owls to range more extensively to find sufficient food.
Which of the following ,if true, most helps to confirm the explanation above?
A.        Some boreal owls range over an area eight times larger than the area over which any other owl of similar size ranges
B.        Boreal owls range over larger areas in regions where food of the sort eaten by small mammals is sparse than they do in regions where such food is abundant.
C.        After their young hatch, boreal owls must hunt more often than before in order to feed both themselves and their newly hatched young
D.        Sometimes individual boreal owls hunt near a single location for many weeks at a time and do not range rather than a few hundred yards.
E.        The boreal owl requires less food, relative to its weight, than is required by members of other owl species.
答案为B。注意题目让你加强的是explanation，即large range是由于scarce food导致的。选项A与此无关，且包含自杀词。