将来完成时的构成
将来完成时的构成是由"shall/will + have +过去分词"构成的。
Before long he will have forgotten all about the matter.
不久他就会全然忘记这件事的。
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。
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？ 

将来完成时的用法
①表示在将来某一时间之前已完成的动作，并往往对将来某一时间产生影响。
We shall 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。
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。

②表示推测，相当于"must have done"结构。
You will have heard of this, I guess.
我想你已经听说过这件事了。
I am sure he will have got the information.
我相信他一定得到了这个信息。 　

注：
在时间状语从句中，不用将来完成时，要用现在完成时来代替。
When I have finished that, I shall have done all I am supposed to do.
等我做完这件事时，我就做完我该做的所有的事了。
Please don't get off the bus until it has stopped.
请等车停稳后下车。 


我们来看两个例子：
1、I will have finished all the work by the time you are back this evening. I am sure he will have left Paris by this time tomorrow. I hope we will have got all the information before you come tomorrow. By the end of this month, we surely____a satisfactory solution to the problem.

A) have found B) will be foundC) will have foundD) are finding

本题时间状语为by+将来时间，考察将来完成时用法,应选择C.

2、The conference____a full week by the time it ends.

A) must have lastedB) will have lastedC) would lastD) has lasted

将来完成时用来可以表示在将来某一时间以前一直持续的动作，本句话的意思是：这次会议将持续整一周才结束，因此谓语动词用将来完成时，答案为B.

练习题：

1. Pick me up at eight o'clock, I ______ my bath by then.
A) will have had B) will be having C) can have had D) may have
2. By the end of this month, we surely ___________ a satisfactory solution to the problem.
A) have found B) will be finding C) will have found D) are finding
3. By the end of the year all but two people _______________.
A) have left B) will leave C) will be leaving D) will have left
4. It's reported that by the end of this month the output of cement in the factory _____ by about 10%.
A) will have risen B) has risen C) will be rising D) has been rising
5. The conference _____________ a full week by the time it ends.
A) must have lasted B) will have lasted C) would last D) has lasted
6. My train arrives in New York at eight o'clock. The plane I would like to take from there _____________ by then.
A) would leave B) will have left C) has left D) had left
7. —May I speak to your manager Mr. Williams at five o'clock tonight?
—I'm sorry. Mr. Williams ____ to a conference long before then.
A) will have gone B) had gone C) would have gone D) has gone
8. By the time he arrives in Beijing, we ____ here for two days.
A) have been staying B) have stayed C) shall stay D) will have stayed
9. By the time you get to New York, I ______ for London.
A) am leaving B) shall have left C) have already left D) would be leaving

Keys:

1. A) 2. C) 3. D) 4. A) 5. B) 6. B) 7. A) 8. D) 9. B)