请牛牛解答 PREP

sunfish223

74.(29534-!-item-!-188;#058&004138)



In a certain wildlife park, park rangers are able to track the movements of many rhinoceroses because those animals wear radio collars.When, as often happens, a collar slips off, it is put back on.Putting a collar on a rhinoceros involves immobilizing the animal by shooting it with a tranquilizer dart.Female rhinoceroses that have been frequently recollared have significantly lower fertility rates than uncollared females.Probably, therefore, some substance in the tranquilizer inhibits fertility.

In evaluating the argument, it would be most useful to determine which of the following?

A. Whether there are more collared female rhinoceroses than uncollared female rhinocerosesin the park

B. How the tranquilizer that is used for immobilizing rhinoceroses differs, if at all, from tranquilizers used in working with other large mammals

C. How often park rangers need to use tranquilizer darts to immobilize rhinoceroses for reasons other than attaching radio collars

D. Whether male rhinoceroses in the wildlife park lose their collars any more often than the park’s female rhinoceroses do

E. Whether radio collars are the only practical means that park rangers have for tracking the movements of rhinoceroses in the park

正确答案是 C 不太明白哦 @@

flames001

本人愚见

此题的句子中心不在结论，关键在Putting a collar on a rhinoceros involves immobilizing the animal by shooting it with a tranquilizer dart. Female rhinoceroses that have been frequently recollared have significantly lower fertility rates than uncollared females.
这两句话告诉我们，using tranquilizer darts to immobilize rhinoceroses 导致significantly lower fertility rates，也就是注射导致低受精率。（所以结论是some substance in the tranquilizer inhibits fertility）
这个逻辑是由是一个事实+一个现象推理而得。
事实：Putting a collar on a rhinoceros involves immobilizing the animal by shooting it with a tranquilizer dart.
现象：Female rhinoceroses that have been frequently recollared have significantly lower fertility rates than uncollared females.
表面上看起来，逻辑推理很充分。
如何去评价这样一个逻辑：注射导致低受精率。
C答案的意思是，除了要给犀牛戴项圈的情况之外，还有没有其他情况会使用tranquilizer darts to immobilize rhinoceroses 。
回答“是”，即其他情况下也会使用tranquilizer darts to immobilize rhinoceroses ，则削弱argument
回答“否”，则加强了推理。

此题，如果去评价结论therefore, some substance in the tranquilizer inhibits fertility，永远也找不到答案。

sunfish223

非常感谢！！！