Question

The course normally attracts 20 students per year, ________ up to half will be from overseas．

1. A.
   for whom
2. B.
   of whom
3. C.
   with which
4. D.
   in which

Answer 1

B
解题思路：本题属于非限定性定语从句．句意指人，可先排除A、C两项．把该句分解成两个独立的句子：The course normally attract 20 students per year；up to half of them will be from overseas.可以看出，half后应接of them．