英语语法之将来完成时与过去将来完成时思维导图

在将来某一时刻之前开始的动作或状态

by the time of; by the end of + 时间短语（将来）；by the time + 从句（将来）

主语 + be going to/will/shall + have + p.p（过去分词） + 其它

By the time you get back, great changes will have taken place in this area. 到你回来的时候，就将发生巨大的变化。

表示在过去某一时间对将来某一时刻以前所会发生的动作，常用在虚拟语气中，表示与过去的事 实相反。

should/would have done sth.

I thought you'd have left by this time.我想这会儿你已经走了

He told them he would have finished it by 8 o'clock.他告诉他们他会在8点以前干完。