【题目】The children，__________ had played the whole day long, were worn out.
A. all of what B. all of which
C. all of them D. all of whom
在线课程【答案】D
【解析】句意：孩子们因为玩了一整天，都已经精疲力竭了。本题考查定语从句的用法。先行词为the children，将先行词代人定语从句后为：All of the children had played the whole day long. 由此可见，先行词在定语从句中作of的宾语，且先行词表示“人”，故只能用all of whom。