—What time will Mr. Brown be back to China? —Sorry. I don’t know.A. when did he go abroadB

问题补充：

—What time will Mr. Brown be back to China?

—Sorry. I don’t know.

A. when did he go abroad

B. why he is going abroad

C. how soon will he be back

D. how long he will stay abroad

答案：

A. when did he go abroad

B. why he is going abroad

C. how soon will he be back

(答案→)D. how long he will stay abroad

解析：本题回答语know后跟的是一个宾语从句，应该用正常的陈述句顺序，故不选AC，本题上句问的是时间，回答语和时间有关的只有D项，故本题选D。