请问这个题是什么结构呢？是定语从句吗？

Today's English learners have a wide choice of dictionaries(  )to choose.

A. from which   B. in which   C. for whih   D. of which

答：该结构是“介词 +which +to do”，相当于一个定语从句。该题答案为A。

具体说来，介词＋which/whom＋to do 结构可以改为：介词＋which/whom＋定语从句。如：

  I don't have enough money with which to buy such an expensive dress.

＝I don't have enough money with which I can buy such an expensive dress.