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标题: prep 逻辑一道~！ [打印本页]

作者: shunliqumeiguo 时间: 2010-11-14 12:30
标题: prep 逻辑一道~！

22.(28162-!-item-!-188;#058&003858)

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.

答案A

E为什么不对呢？？E是说在动物的组织中检测出了除草剂中的毒素。我理解有错吗？？？为什么不对呢？？？

作者: winzero 时间: 2010-11-14 17:20
但是这个毒素不一定就是致使鸟数量减少的原因啊，

作者: eshopaholic 时间: 2010-11-15 14:34
E 从侧面支持了结论。

The toxins contained in herbicides typically used on cereal crops can be readily identified in the tissues of animals that have ingested them

意思是：对于吃过相关农作物的动物，很容易在它们的组织中鉴定出除草剂的毒素。

作者: jbc88 时间: 2010-11-15 17:12
(E) The toxins contained in herbicides typically used on cereal crops can be readily identified in the tissues of animals that have ingested them.

E说对于吃过相关农作物的动物，很容易在它们的组织中鉴定出除草剂的毒素。

不一定这动物就是鸟啊

作者: shunliqumeiguo 时间: 2010-11-15 19:26
原来如此！！！

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