一、过去将来完成时和将来完成时从字面的意思上看，它们的区别就在于时间，过去将来完成时，强调的是过去的时间，而将来完成时强调的是将来的时间，两者都是在将来的时间事情已经完成，例如：
1. The day was not so far when we would have finished this project.
我们完成这个项目的日子不远了。
2. He said he would have done with my camera by the end of next month.
他说到下月底就不用我的照相机了。

二、将来完成时是用在表示在将来某一时间以前已经完成或一直持续的动作。经常与before+将来时间或by+将来时间连用，也可与before或by the time短语引导的现在时的从句连用。例如：
1.Before long he will have forgotten all about the matter.
不久他就会全然忘记这件事的。
2.He is somebody now. He will not have remembered his old classmates.
他现在是一个有身份的人了，他可能不会记得老同学了。
3.Will you have known Kevin for 10 years next month?
到下个月你认识凯文该有10年了吧？
4.Pick me up at 8 o'clock,I will have had breakfast by then.
早上8点钟你来接我，到时我已经吃完早饭了。
5.We will have learned 12 units by the end of this term.
到这个学期末，我们将学完12个单元。
6.By the time you get home I will have cleaned the house from top to bottom.
你到家之前我将把房子彻底打扫一遍。
7.You will have heard of this, I guess.
届时我想你已经听说过这件事了。
8.I am sure he will have got the information.
我相信他一定会得到这个信息。
9.We will have been married a year on June 25th.
到6月25日我们俩结婚就满1年了。
10.They will have been married for 20 years by then.
到那时他们俩结婚就满20年了。