逻辑prep--22,E选项，思路分析讨论

alicejingli

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?

思路：H开始用，P变少à被毒死了

用H的地上，P体内的H不比没有H的地方多，因此其他原因导致

削弱，就是H导致的

(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. H导致W少，导致虫少，导致鸟少【注意不一定要是毒死的】

(B) Since partridges are valued as game birds, records of their population are more carefully kept than those for many other birds.记录详细无关

(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.跟应不应该用药无关

(D) Birds other than partridges that live in or around cereal crop fields have also been suffering population declines.什么影响的，还是不知道是不是H影响的

(E) The toxins contained in herbicides typically used on cereal crops can be readily identified in the tissues of animals that have ingested them.这个是因为鸟类的体内组织中包含毒素但是题目中并没有说明毒素包含多少对鸟类会有影响，特别是对于减少P数量的影响，所以不能用常识——体内有毒素的鸟就是因为毒素死掉的——推论。

以上是我的思路，大家觉得对吗？

这题选A

还有问问各位，大家觉得这道题算什么类型的，从题目到答案不确定到底是哪种削弱？一般的类型，努力贴着原文的逻辑走的类型？

powers

搞不懂!
我来乱说几句.
反而觉得E是在加强这个推理的前面部分...
"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."

因为这个毒素非常容易辨识,但是还是没查出来,反而更strength了...

littlexian

Your thinking is correct.

Weaken the argument- something other than herbicide use must be responsible for the population decrease-

So, we need to prove that "H is responsible"

The toxins contained in herbicides typically used on cereal crops can be readily identified in the tissues of animals that have ingested them. - It just says that there will be no mistake to misidentify the herbicides in any birds what have eaten them.  

It just proves that "tests show no more than trace quantities of herbicides in partridges on herbicide-treated land" is correct, a fact, no mistake possibly invloved. However, it does not weaken the argument, something other than herbicide use must be responsible for the population decrease, at all.

powers

选A是吧,一开始以为你说选OA是D,差点把我搞得一头雾水...