66. Male bowerbirds construct elaborately decorated nests, or bowers. Basing their judgment on the fact that different local populations of bowerbirds of the same species build bowers that exhibit different building and decorative styles, researchers have concluded that the bowerbirds’ building styles are a culturally acquired, rather than a genetically transmitted, trait. Which of the following, if true, would most strengthen the conclusion drawn by the researchers? (A) There are more common characteristics than there are differences among the bower-building styles of the local bowerbird population that has been studied most extensively (B) Young male bowerbirds are inept at bower-building and apparently spend years watching their elders before becoming accomplished in the local bower style. (C) The bowers of one species of bowerbird lack the towers and ornamentation characteristic of the bowers of most other species of bowerbird. (D) Bowerbirds are found only in New Guinea and Australia, where local populations of the birds apparently seldom have contact with one another. (E) It is well known that the song dialects of some songbirds are learned rather than transmitted genetically.
67. A greater number of newspapers are sold in Town S than in Town T. Therefore, the citizens of Town S are better informed about major world events than are the citizens of Town T. Each of the following, if true, weakens the conclusion above EXCEPT: (A) Town S has a larger population than Town T. (B) Most citizens of Town T work in Town S and buy their newspapers there. (C) The average citizen of Town S spends less time reading newspapers than does the average citizen of Town T. (D) A weekly newspaper restricted to the coverage of local events is published in Town S. (E) The average newsstand price of newspapers sold in Town S in lower than the average price of newspapers sold in Town T.
68. A drug that is highly effective in treating many types of infection can, at present, be obtained only from the bark of the ibora, a tree that is quite rare in the wild. It takes the bark of 5,000 tree to make one kilogram of the drug. It follows, therefore, that continued production of the drug must inevitably lead to the ibora’s extinction. Which of the following, if true, most seriously weakens the argument above? (A) The drug made from ibora bark is dispensed to doctors from a central authority. (B) The drug made from ibora bark is expensive to produce. (C) The leaves of the ibora are used in a number of medical products. (D) The ibora can be propagated from cuttings and grown under cultivation. (E) The ibora generally grows in largely inaccessible places.
69. High levels of fertilizer and pesticides, needed when farmers try to produce high yield 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) 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.
答案： 66. The information in choice B says that young bowerbirds progress slowly toward mastery of a bower-building style, which suggests that the skill is one they must learn, rather than one whose transmission is wholly genetic. Choice B also suggests a means of cultural transmission, namely, observation of older birds’ technique. Thus, B supports the conclusion and is the best answer. That differences within building styles are outnumbered by similarities (choice A) and that local populations have little contact (choice D) are both equally consistent with building-style differences being culturally acquired or genetically transmitted. Nor are differences among species of bowerbird (choice C) the issue. Finally, choice E confirms the possibility of birds leaning skills, but it is not evidence that bower-building styles are learned.
67. The conclusion is based on comparing newspaper sales in Town S and Town T. Four answer choices indicate why greater newspaper sales in S need not imply that citizens of S are better informed about world events. Choice B suggests that many newspapers sold in S inform citizens of T, not S. Choices A and C both show how greater newspaper sales can occur without the average citizen having greater familiarity with the news. Finally, choice D suggests that much newspaper reading in S is not a source of information about world events. The price differential noted in E might help to explain the difference in sales, but it does not undermine the conclusion based on that difference. Therefore, E is the best answer.
68. If the ibora can be successfully cultivated, it is possible to continue production of the drug without threatening the ibora with extinction. Therefore, choice D is the best answer. If production continues, the method for distributing the drug aftr it has been produced (choice A) is not likely, on its own, to have consequences for the continued existence of the ibora. Nor is the price of the drug (choice B). If the leaves of the ibora also have a use (choice C), the threat of extinction is strengthened rather than weakened. Finally, if the ibora is largely inaccessible (choice E), this bears on the question of whether production of the drug could continue, not on what would happen if it did continue.
69. Farmers benefit from governmental price supports only when they produce the same crops from year to year. Farmers who wish to receive the benefit of these price supports will be unlikely to reduce water pollution because they will not follow the experts’ advice regarding diversification and rotation. Thus, A is the best answer. Since the experts’ advice is evidently their favored solution, the notion that the sole solution is something else (choice B) is not supported. The statements mention neither farmers’ cost and revenues nor developments in farming techniques, and thus support no conclusions about prospects for profits (choice C) or future farming techniques (choice D). Because no information is given about either the amount of price support or farmers’ debt, choice E is not supported.
P:different local populations of bowerbirds build bowers that exhibit different building and decorative styles, C: bowerbirds’ building styles are a culturally acquired.
P:different local populations of bowerbirds build bowers that exhibit different building and decorative styles, C: bowerbirds’ building styles are a culturally acquired.
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发表于 2011-11-1 21:51:51
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