一直找不到對應題號..快要考試了..直接問了

yorksha

不好意思 請問下面這題:

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 bacteria for many tick larvae.

E. None of the other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans.

Answer: C

請問C為何能strengthen??

Tks a lot!!!

skyzhang

鹿虫在幼虫期间通过进食感染的老鼠而感染病菌。鹿虫幼虫吃的其他东西无细菌，因此如果其他东西多了，幼虫就不会得病。（幼虫就去吃其他东西去了，不会吃那个老鼠了。）

其实读完你就会觉得奇怪了，幼虫是可以吃其他事物，但是并不妨碍它吃老鼠啊，它可以早饭吃其他食物，晚饭就吃老鼠啊。

C选项其实就是排除这一项。幼虫只能吃一次，这样情况下，如果其他食物多，它吃到其他食物的机会就多，感染的机会就少。

yorksha

Thank you skyzhang

I got your point!!

之前一直想不通的是 只吃一次=> 增加吃到"未感染"mice的機率=>可以降低ticks acquire bacterium

那麼如果不只吃一次 就無法增加吃到"未感染"mice的機率 嗎?

後來想想 只要"只吃一次"的效果>"吃好幾次" 其實就足以符合strengthen了

而且其他選項更不理想 所以還是選C較佳^^

very happy to solve this problem~~