问题
选择题
The children, _____ had played the whole day long, were worn out.
A．all of what
B．all of them
C．all of whom
D．all of which
答案
答案：C
题目分析：考查非限制性定语从句，句意：那些玩了一整天的孩子们，都已经累坏了。首先先行词是the children是指人的，排除AB，them不能引导从句，这里是不定代词all+介词+whom引导定语从句，选C。