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标题: T-4-Q13 G-12-Q16 没有找到链接 [打印本页]

作者: happywawa 时间: 2008-8-15 00:48
标题: T-4-Q13 G-12-Q16 没有找到链接

T-4-Q13 G-12-Q16:

Certain genetically modified strains of maize produce a natural insecticide that protects against maize-eating insects. The insecticide occurs throughout the plant, including its pollen. Maize pollen is dispersed by the wind and often blows onto milkweed plants that grow near maize fields. Caterpillars of monarch butterflies feed exclusively on milkweed leaves. When, in experiments, these caterpillars were fed milkweed leaves dusted with pollen from modified maize plants, they died. Therefore, use of the modified maize inadvertently imperils monarch butterflies.

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

Per unit of volume, the natural insecticide produced by the genetically modified maize plants is less toxic to insects than are many commercial insecticides commonly used on maize plants.
Standard weed-control practices that have been used by farmers for decades have largely eliminated milkweed plants from certain areas where monarch-butterfly caterpillars were once common.
The experiments showed that the caterpillars were not harmed by contact with the pollen from the genetically modified plants unless they ingested it.
The maize-eating insects that the natural insecticide protects against do not feed on the pollen of the maize plant.
Airborne maize pollen tends to collect on the middle leaves of milkweed plants and monarch caterpillars feed only on the plant’s tender upper leaves.

答案是E，我觉得是找不到答案。

E. 原文说these caterpillars were fed milkweed leaves dusted with pollen from modified maize plants, they died. 那么E，及时把中间取走了还是会有dust在upper leaves的啊？

当然相比其它答案只能选E了。不知道我是不是专牛角尖了，请NN指教啊。

其它选项的分析如下：

A 这个比较无关，原文没有提到commercial insecticides

B 去除milkweed和结论蝴蝶受到危及原因：吃的milkweed leaves有pollen dust 是没有关系的啊

C 这个和文章的前提不同，前提原因已经说了吃了有pollen dust的milkweed leaves，所以无关。其实我开始选的是这个。

D 无关选项

作者: Gudjohnson 时间: 2008-8-15 04:34
毛毛虫都吃上面的叶子；而飘落的花粉只是落在叶子的中间部分。weaken

作者: happywawa 时间: 2008-8-15 14:07

谢谢Gudjohnson

原来是我没有把E选项读懂

请问C是改变了原文的前提，所以不可能是正确选项吗？

[此贴子已经被作者于2008-8-15 14:08:03编辑过]

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