When the meeting was over he writing a report about it immediately.A. set offB. set outC

问题补充：

When the meeting was over, he writing a report about it immediately.

A. set off

B. set out

C. set forth

D. set about

答案：

A. set off

B. set out

C. set forth

(答案→)D. set about

解析：短语辨析。A. 出发；引起 B. 出发；开始C. 陈述；提出 D. 开始做。句意：当会议结束时，他立即开始写会议报告。故选D。