题目内容：

The thief ___ the bank when the police arrived.
A、fled B、flee from C、had fled from D、fled from

优质解答

C,过去完成时.动作（flee）发生在过去（arrived）的过去.

追问：

再请教你几道题：His answer _____ a heated argument. A、set out B、set up C、set off D、set in After people discovered gold in California,it ___ a rush to get there. A、set back B、set out C、set up D、set off

追答：

这两题的答案都是set off，意思是“引发，激发”