PREP 1-92

binghefeng

Kate:  The recent decline in numbers of theTennessee warbler, a North American songbird that migrates each fall to coffeeplantations in South America, is due to the elimination of the dense tree coverthat formerly was a feature of most South American coffee plantations.


Scott:  The population of the spruce budworm, the warbler'sfavorite prey in North America, has been dropping.  This is a more likely explanation of thewarbler's decline.

Whichof the following, if true, most seriously calls Scott's hypothesis intoquestion?

A.The numbers of the Baltimore oriole, a songbird that does not eat budworms butis as dependent on South American coffee plantations as is the Tennesseewarbler, are declining.
B.The spruce budworm population has dropped because of a disease that can infectbudworms but not Tennessee warblers.
C.The drop in the population of the spruce budworm is expected to be onlytemporary.
D.Many Tennessee warblers have begun migrating in the fall to places other thantraditional coffee plantations.
E.Although many North American songbirds have declined in numbers, no otherspecies has experienced as great a decline as has the Tennessee warbler.

选A的理由无非是：通过(无A也有B) 来进行weaken
但是这道题目不是改变了范围吗？原文说的是warbler，而正确选项说的却是Baltimore oriole。我第一时间就把A给排除了。