PREP

96.
            (29707-!-item-!-188;#058&003977)

In some species of cricket, the number of chirps per minute used by the male for attracting females rise and fall in accordance with the surrounding temperature, and they can in fact serve as an approximate thermometer.

(A) for attracting females rise and fall in accordance with the surrounding temperature, and they can in fact serve

(B) for attracting females rises and falls in accordance with the surrounding temperature, which can in fact serve

(C) in attracting females rise and fall in accordance with the surrounding temperature, in fact possibly serving

(D) to attract females rises and falls in accordance with the surrounding temperature, and it can in fact serve

(E) to attract females rises and falls in accordance with the surrounding temperature, in fact possibly serving

为什么选D.IT 指代什么

我认为此题目有考察以下的几点：

1) the number of chips 做主语谓语用单数, 所以必须要用rises and falls

2)在GMAT 当中表目的一般要用to do.

3)原题目中有情态动词的,一般不能任意更改或者删除, 所以can 若变成possibly ,语意改变很大

4)sevrve 在题目中的意思不应该用伴随.

IT我觉的应该是指代the number of chirps .

若有不对的地方,还请牛牛更正.