请教prep1-96的指代问题

waynepolestar

prep SC part1 96

    

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

答案是d，确实应该考虑can的情态动词保持。

但是看了前人的帖子，好像没有人回答it的指代问题。但是感觉serve应该是修饰前面 rises and falls in
accordance with the surrounding temperature的吧。不甚明了。难道真的修饰number?

georgelhb

it = the number of chirps
per minute

schumi

来看解释