问题补充：
There were two boys in the lab,did the experiment successfully.
A. the clever of whom
B. the cleverer or whom
C. the clever of them
D. the more clever of them
答案：
A. the clever of whom
(答案→)B. the cleverer or whom
C. the clever of them
D. the more clever of them
解析：选B。“the + 形容词比较级+of+名词复数”表示“两者中较…的一个”；此处关系代词whom指代the two boys.
