GWD-3-Q38,难道没人有想过南、北美洲的问题？

annieguan

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.

当然我自己选择下来也是A，不过我觉得这个答案还不够完美~~

因为你们看，Kate说，生长于North America的TW每年飞到South America,现在数量少是因为South America那里的问题；但是S说，是因为North America自己那里Worm的问题。然后A选项又说BO的例子可以佐证。可是又没有说清楚BO这个鸟是和TW一样从north-->south，还是本来就是south？如果这个BO本来就在south America，其实也不能算是对Scott的削弱，因为Scott的说法是North America那里的问题~~

对不对？？

HarrisZheng

不对

本题特别要求排除scott举出的它因

即便把 A改成 The numbers of the Baltimore oriole, a songbird that eats budworms elsewhere but is still as dependent on South American coffee plantations as is the Tennessee warbler, are declining.

BO这种鸟 能在别处吃饱 但是依赖这些咖啡树 数量也减少了

我们还能加上更严格的条件 BO天天有人喂吃的给他 吃得个个膘肥体壮 但到南美来 数量还是减少

所以 A其实个容错程度很高端的驳斥： 有“依赖咖啡树数量就减少”这个条件在，它可以是个万能驳斥，可以驳斥一切它因，更不用说题目要求的仅仅驳斥scott了。

HarrisZheng

或者换个简单的说法

eat budworms 包含了 eat budworms in North America

驳斥了全集，自然也就驳斥了子集。