求教，PREP07-2-120，疑问

ying178

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
答案是D，因为FUNCTION AS，所以我也选的D。
我的疑问是：语法笔记说A的错误是不一致，Their与未划线部分the turtle has been的数不一致”但我疑惑的是，如果有一个选项是：its horny jaws function as teeth. 那么就对了吗？
有了in some species之后，the horny jaws 到底是谁的？是跟 some species还是the turtle?

ying178

自己顶一下，盼望解答

mliu9

答案是E。。。你在确认下

ying178

是E，不好意思，我敲错了。我对答案无异议。
就是想问一下PREP语法笔记的解释中，说their和the turtle数不一致，我不知道有了in some species之后，是不是their是对的？

miffyhui

Lz,答案为什么不是D？？不理解，求解答