[求助]TT GWD-6-13

silviaqiu

Q13:

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 larval 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?

 

1. Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.
2. There are no known cases of a human’s contracting Lyme disease through contact with white-footed mice.
3. A deer tick feeds only once while in the larval stage.
4. A single host animal can be the source of bacteria for many tick larval. (C)
5. None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.

这个c选项怎么觉得一看就像个无关项啊

silviaqiu

顶!

biss33

我们把deer tick吃的东西分为两类，一种是mice,一种是other species.假如deer tick在laval stage要喂多次的话，很有可能既吃mice，又吃other species,所以即使增大了other species的数量的话，deer tick还是要吃mice.

但是假如deer tick只吃一次的话，增加other species 的数量，铁定会减少吃mice的机会，所以deer感染的机会就小了 

silviaqiu

真是一个相当牵强的选项

zhaoyak7

以下是引用silviaqiu在2006-7-23 17:10:00的发言：

Q13:

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 larval 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?

 

1. Ticks do not suffer any adverse consequences from carrying the bacterium that causes Lyme disease in humans.
2. There are no known cases of a human’s contracting Lyme disease through contact with white-footed mice.
3. A deer tick feeds only once while in the larval stage.
4. A single host animal can be the source of bacteria for many tick larval. (C)
5. None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.

我觉得C不牵强啊，而且相当标准，楼上解释的也清楚。A的any adverse consequences无关，B的no known 并不能说明没有。D延伸大发了，E是否有其它的细菌会传染到人，原文没说。我一开始看题干，第一感觉是出削弱题。其实我觉得C做为假设题的答案更贴切，取非，就削弱了。再次感到，把握整个题意太重要的。

yunhan123

同意楼上的，本题属于假设类加强题。说实话，题意不好理解。

crystal2003

我觉得刚开始没有理解C选项的原因是,没有注意到the population are increased 而不是increased.如果看成increased就很难理解本题的逻辑.

saroya

still not sure...

saroya

不是吃一次，若多次吃，就没效？？I still don't understand

mjfanshome

yes!