百思不得其解的一道逻辑 weaken的中心到底是怎么找啊？

monica928

Herbicides allow cereal crops to be grown very efficiently, with virtually no competition from weeds.  In Britain, partridge populations have been steadily decreasing since herbicide use became widespread.  Some environmentalists claim that these birds, which live in and around cereal crop fields, are being poisoned by the herbicides.  However, tests show no more than trace quantities of herbicides in partridges on herbicide-treated land.  Therefore, something other than herbicide use must be responsible for the population decrease.

Which of the following, if true about Britain, most seriously weakens the argument?

(A)  The elimination of certain weeds from cereal crop fields has reduced the population of the small insects that live on those weeds and that form a major part of partridge chicks' diet.
(B)  Since partridges are valued as game birds, records of their population are more carefully kept than those for many other birds.
(C)  Some of the weeds that are eliminated from cereal crop fields by herbicides are much smaller than the crop plants themselves and would have no negative effect on crop yield if they were allowed to grow.
(D)  Birds other than partridges that live in or around cereal crop fields have also been suffering population declines.
(E)  The toxins contained in herbicides typically used on cereal crops can be readily identified in the tissues of animals that have ingested them.

这道题正确答案是A
我始终觉得A不是weaken，而是加强的。
我觉得结论应该是最后一句：其他原因导致P鸟减少
但是A中的杀虫剂杀死了鸟吃的虫子 就是其他原因啊 虫子死了是原因，而不是杀虫剂的原因直接导致鸟死的

但是 此题如果weaken的是前面科学家的话 就是说别的原因可以导致鸟死
就是对的

我想知道大家都是怎么找CR的中心点的？

有没有人解答一下我的困惑。谢谢~~~~

monica928

顶一下~~~米人么？

jiankai

答案A
原文结论：不是 herbicide，而是其他原因，导致p鸟减少
   削弱：不是其他原因，就是herbicide，导致p鸟减少

选项的中心----找出p 鸟减少的原因
A；herbicide---》p鸟减少，削弱

monica928

呵呵 对  有时候在逻辑题里面绕绕就晕了~~跳出来想想就对了
还是要写逻辑链 不然容易出错