Future Perfect Tense

What is Future Perfect Tense? How is it made?

1. Future perfect tense tells us that an action will be finished or completed before some specified time in the future.
For example:
* At 8'o clock, I will have finished my homework.
* We will have gone to bed, by the time we get home.

2. Future perfect tense is also used to talk about the near past. It is used to talk about actions that have just finished in the near past and you are sure about it, but It may have not finished. 
For example:
* The bus will have left. (The bus leaves at 10. Maybe the bus is late.)
* Don't go now, he'll have gone. (Maybe, he has not gone yet.)
(In this sense, you say something based on your experience.)

Commonly used time expression in Future perfect tense:

*by
*by the time/ by now / 
*before
*by tomorrow
*next month/year/week
*till/untill

Sentence Structure of Future Perfect Tense:

Positive:
Subject + will have + 3rd form of verb +.......
He + will have + finished + his work + by tomorrow.
Negative:
Subject + will have not + 3rd form of verb +....
He + will not have + arrived.
Interrogative:
Will + subject + have + 3rd form of verb + ...... ?
Will + he + have + reached?