问题
选择题
The tourists, had enjoyed themselves so much in the botanic garden, were worn out
A．all of what
B．all of which
C．all of them
D．all of whom
答案
答案：D
题目分析：句意：在植物园玩得很高兴的所有的游客都精疲力竭了。这里使用了定语从句，先行词是the tourists，定语从句是由代词all+介词of+关系代词引导的，因为先行词是人，所以关系代词用whom，选D。