划分下句子结构啊和解释原因

题目

划分下句子结构啊和解释原因
The computer programs are a puzzle to me.The more I think of them,the more questions I think of____.A.ask B.asked C.being asked D.to ask为啥选D?

答案

D
The more I think of them,the more questions I think of to ask.
the more questions I think 中,the more questions是先行词
原句应该是the more questions （that）I think of to ask.
因为that是做I think of 的宾语,所以可以省略.
the more questions I think of其实已经完整
to ask表示目的,“去问”
原句：我想得越多,我越有问题想去问.