prep2-120 代词指代

120.      (30893-!-item-!-188;#058&005903)

Although the turtle has been toothless for more than 150 million years, in some contemporary turtle species the moderately sharp and jagged edges of their horny jaws function for teeth.

(A) their horny jaws function for teeth

(B) its horny jaws function for teeth

(C) its horny jaws function as do teeth

(D) the horny jaws function as teeth do

(E) the horny jaws function as teeth

key E

prep解释说A 中的their 与 the turtle不一致，可是我觉得既然是在  in some contemporary turtle species里而且用了edges 这里也可以用their啊，怎么就只一种turtle呢？

species单复数同形。its指代错误。their指代species。

但是我不知道their jaws跟the jaws的区别。只是读起来感觉是the jaws更好。

多谢aeoluseros和dingxiang

 in some contemporary turtle species the moderately sharp and jagged edges of their horny jaws 我觉得主语好像是 edeges吧，从句说turtle没有牙齿，但是在其他种类里这里用了species,他们的edges function as牙齿，而且这里谓语也是function.复数， 这里的their怎么能向前指代the turtle呢？

难道不是在比较中， as侧重于动作上的比较和句子比较， like侧重于物的比较。

那d为什么不对呢？

同意用the horny jaws做泛指在这里比较合适

这边我有一个问题是 in some contemporary tu and jagged edges of the horny jaws function as teeth.

这句主词是turtle species 是单数形还是复数形？

然后这句的动词是？

我有点疑惑「the moderately sharp and jagged edges of the …..  」

究竟是做什么成份？

请NN解惑……

rtle species the moderately sharp