过去式的动词三单We watched the train leave(为什么不用leaves?) the station

过去式的动词三单We watched the train leave(为什么不用leaves?) the station could you tell me when the train leaves?这里为什么不用will leave,为什 Unluckily,the train( ) when we got to the station (leave) the train ____(leave) by the time we arrived at the station 填空1 When we arrived at the station ,the train ______(leave). can we arrive at the station before the train __（leave） 为什么要用does?When does the train leave the station? He didn't catch the train that leaves at 8 o'clock.为什么是leave the train ___(leave)when i __(got)the station please ()when the train leaves i will leave for The train leaves the station at six o'clock.对划线部分提问 划线的是at s By the time we()the railway station,the train