求指教，36套里面的一道逻辑题。。

麻倉枼UID: 3376337

我要的不是答案，答案我有了。。
我想请教的是思路，
希望各位朋友们详细点讲下自己的思考思路。。
谢谢啦。。我可能真的有点脑残了。。EX 25， 2/10。

麻倉枼UID: 3376337

Over the last 40 years there has been a great increase not only in the number of agricultural pesticides in use but also in the care and sophistication with which they are used by farmers. Nevertheless, the proportion of agricultural crops lost to certain pests worldwide has increased over the same period, even when the pests concerned have not developed resistance to existing pesticides.


7. Which of the following, if true. best explains how improvements in pesticide use have been accompanied by greater losses to certain pests?

(A) Some dangerous but relatively ineffective pesticides common 40 years ago are no longer in widespread use.

(B) As pesticides have become increasingly pest- specific, controlling certain pests with pesticides has turned out to cost more in many cases than the value of crop losses caused by those pests.

(C) Because today's pesticides typically have more specific application conditions than did pesticides in use 40 years ago, today's farmers observe their fields more closely than did farmers 40 years ago.

(D) Certain pest-control methods that some farmers use today do not involve the use of chemical pesticides but are just as effective in eliminating insect pests as those that do.

(E) Forty years ago, much less was known about the effects of pesticides on humans and other mammalian species than is now known.

tracy910223UID: 3318518

开始我也不明白
看完了解析想想是这么个道理

开头应该是说杀虫剂的数量变多了，但随之而来的农民在想到底用哪个的这种考虑也增加了！
害虫多，吃庄稼要花钱；但是使用杀虫剂也要花钱；如果不划算，农民就不愿意用了！
就是这样的一个关系。

GBFUID: 3379645

麻倉枼 发表于 2013-1-15 13:40
Over the last 40 years there has been a great increase not only in the number of agricultural pestic ...

我一直没时间复习逻辑这部分，第一眼看上去，是选B 吗？

crazyrobinUID: 2368627

这道题的问题是让你解释一个discrepancy，为什么杀虫剂的（发展，技术）进步了，反而某一种害虫对农产品造成的伤害更大了。

A选项没什么作用，40年前一些不太有作用的杀虫剂不再使用了并不能解释这个矛盾
B杀虫剂针变得越来越针对某类害虫，这样对于农民来说使用杀虫剂的成本太大，因此经过考虑后放弃了使用这种杀虫剂，这个刚好解释了为什么杀虫剂技术进步，反而造成某种害虫的危害更大这个矛盾。
C没效果，说在使用时候有更多限制，所以农民需要综合考量多种因素。但这个解释不了为什么有这样一个矛盾（时刻记得这题是要解决杀虫剂进步和害虫危害更大这个矛盾）
D没效果，说是只能杀一些昆虫，这根某种特定Specific害虫没关系
E对人类和哺乳动物的影响，对解释这个矛盾没有效果。

这个题你需要看清题目问什么，问题在这里是解释矛盾。


还有一个解法就是你看到这个矛盾的时候——也就是杀虫剂技术进步，specific害虫伤害更大，直接看选项找两个关键词 pesticide advance, specific pests
这几个词只在B选项里反映了