Question

He has three children,         are doctors.

1. A.
   and two of whom
2. B.
   two of them
3. C.
   two of whom
4. D.
   two of which

Answer 1

C
这题考查句子结构，因为先行词是children，定语从句要用whom，如果是and连接的并列句，要用and two of them，所以选C。