GWD3-Q38: Kate: The recent decline in numbers of the Tennessee warbler, a North American songbird that migrates each fall to coffee plantations in South America, is due to the elimination of the dense tree cover that formerly was a feature of most South American coffee plantations. Scott: The population of the spruce budworm, the warbler’s favorite prey in North America, has been dropping. This is a more likely explanation of the warbler’s decline. Which of the following, if true, most seriously calls Scott’s hypothesis into question? A. The numbers of the Baltimore oriole, a songbird that dose not eat budworms but is as dependent on South American coffee plantations as is the Tennessee warbler, are declining. B. The spruce-budworm population has dropped because of a disease that can infect budworms but not Tennessee warblers. C. The drop in the population of the spruce budworm is expected to be only temporary. D. Many Tennessee warbler have begun migrating in the fall to places other than traditional coffee plantations. E. Although many North American songbirds have declined in numbers, no other species has experienced as great a decline as has the Tennessee warbler.
答案是A, 我觉得不充分呀,因为Baltimore decline 不能就说明Warbler decline 不是Spruce budworm的decline作为主要原因 造成的呀. 比如说 Baltimore 可能是被猎人打了,但是和Warbler 好象没有关系呀,尽管B as dependent on South American coffee plantations as is the Tennessee warbler.又怎么样呢?
有可能B被猎人打走了,但是W还是因为没有吃到S才少的呀.我觉得这种类比不严密呀.
虽然其他选项也不对,可是我第一个就排除了A, 请NN指教.
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