1、Could you make sure---------- ? A 、when the train leaves B、if the train had left C······

题目

1、Could you make sure---------- ? A 、when the train leaves B、if the train had left C······
1、Could you make sure ?
A 、when the train leaves B、if the train had left
C、when the train would leave D、where has the bus gone

答案

A.
这里could表示委婉的语气,并不表示过去式,因此选择A.
B中had left 没有使用过去完成时的道理,C would应该是will,D没有这种说法.