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标题: 本月一道CR的JJ,大家来讨论 [打印本页]

作者: rokey    时间: 2006-11-19 19:09
标题: 本月一道CR的JJ,大家来讨论

Lyme disease is caused by a bacterium transmitted to humans by deer ticks. Generally deer ticks pick up the bacterium while in the larval stage from feeding on infected white-footed mice. However, certain other species on which the larvae feed do not harbor the bacterium. Therefore, if the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease would likely decline.  

Which of the following, if true, most strengthens the argument?  

A. Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.

B. There are no known cases of a human’s contracting Lyme disease through contact with white-footed mice. 
C. A deer tick feeds only once while in the larval stage.
D. A single host animal can be the source of bacterium for many tick larvae.
E. None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans

据说答案是C,可是我觉得是E.请NN指点


作者: 幽幽sally    时间: 2006-11-19 19:40

E 的other bacteria 是无关啊

再者,就算有好了,答案要加强的是2个内容,E最多只加强了一层

结论是if the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease would likely decline.   而E只加强了and后面的内容

 

不知道说的对不?

欢迎讨论!


作者: rio    时间: 2006-11-19 20:05

就算E说的正确,

其他的细菌也和Lyme是无关的,


作者: rokey    时间: 2006-11-19 20:58
二楼的朋友说得不错,可是我觉得C也没怎么加强啊,这是GWD的题么,我怎么没找到原题,那位好心人帮帮忙,谢谢
作者: giantddu    时间: 2006-11-20 00:59

这就是一道数学题啊,一个盒子中有10枚硬币,9和一元的,1个两元的。

抽一次是两元的概率是1/10,

抽两次至少有一次是两元的概率(放回样本)的概率是1-0.9^2=0.19

只要 deer ticks只吃一次,那么它得得概率是1/n,要是吃两次就是、、、、

所以题目的确是加强了


作者: rokey    时间: 2006-11-20 08:25
呀,原来是这样,了解了~~谢谢指点!
作者: ellycj    时间: 2006-11-21 16:02

C绝对加强了。

因为排除它因--排除没有feed到细菌的larvae也有机会被mice传染到细菌,从而传染给人。

不过我看到的jj说现在这种题目有所改动,也问weaken, evaluation和assumption.

我很少看到直接问strengthen的

多看看前人的JJ应该会有所帮助。






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