问题补充：
Only when .
A. did he arrive the meeting began
B. he arrived the meeting began.
C. did he arrive did the meeting begin.
D. he arrived did the meeting begin.
答案：
A. did he arrive the meeting began
B. he arrived the meeting began.
C. did he arrive did the meeting begin.
(答案→)D. he arrived did the meeting begin.
解析：考查倒装句，only+时间状语从句，位于句首时，主句倒装，选C，句意是：只有当他到的时候会议才开始。选D。
