He has three children, are doctors.
A. and two of whom
B. two of them
C. two of whom
D. two of which
网友回答
A. and two of whom
B. two of them
(答案→)C. two of whom
D. two of which
解析：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。