问题补充:
He made three good friends in the university, joined the army after graduation.
A. one of them
B. one of whom
C. one
D. one of which
答案:
A. one of them
(答案→)B. one of whom
C. one
D. one of which
解析:考查定语从句。句意:他在大学里面交了三个好朋友,其中之一毕业后参了军。本句先行词three good friends下文逻辑主语,作介词宾语的指人的引导词只能使用whom,故用选B。