C,过去完成时.动作（flee）发生在过去（arrived）的过去.再请教你几道题：His answer _____ a heated argument.A、set out B、set up C、set off D、set inAfter people discovered gold in California,it ___ a rush to get there.A、set back B、set out C、set up D、set off这两题的答案都是set off，意思是“引发，激发”