Question

By the time +过去时,主句用过去完成时 若加一般现在时,主句用现在完成时.若加现在的时间,主句用have d

Answer 1

过去完成时表过去的过去 By the time we reached home,He had left.

Before the meeting started,he had left.

现在完成时表对现在产生了影响

I have learned many words in the last few years

加现在的时间 应该可用I have done it now我已经完成了