__we got to the station,the train had left already

问题描述:

__we got to the station,the train had left already
选when 为什么?since不可以吗、

when 引导的从句,从句用了过去时,主句用过去完成时.只有when才可以这样
since 不可以你的意思是:从句是过去式,主句是过完,那么就只能用when吗?对的