IfirstmetMarythreeyearsagowhenwe()inamiddleschooltogether.选择[a]haeworked[b]hadbeenworking[c]wereworking[d]hadworked请选择,并说明理由为什么选

Question

I first met Mary three years ago when we( ) in a middle school together.
选择[a]hae worked [b]had been working [c]were working [d]had worked
请选择,并说明理由为什么选

Answer 1

选C
when引导瞬间时间状语
不可用完成时
所以只能用过去式,或过去进行时