Identification of the Tense: - The event should have completed in recent past. Ex:-
Rajiv will have gone to school.
I shall have played football.
He will not have studied.
Shall they have lived here?
Usage: - In Future Perfect tense we usually use
Third form of the verb and
Will have (with singular subject) shall have (with plural subject)
In the first sentence" Rajiv will have gone to school." Rajiv a singular noun is followd by will have which in tern is followed by third form of the verb gone. Infact all the perfect tense contains third form of the verb.
In the second sentence"I shall have played football." I although represents a singular pronoun but considered in plural category while applying rules is followed by shall have and third form of the verb played.
In the third sentence"He will not have studied" In this negative sentence not in inserted in between will and have leaving all the rules as such.
In the fourth sentence"Shall they have lived here" Being an interrogative sentenceShall is put before the plural pronoun they followed by have and third form of the verb lived.
Use of Future Perfect Tense:
to express an action which is expected to be completed by a certain time in the future.
By the end of this year he will have saved a lot of money.
Before you go to see him, he will have left for London.
In this respect it is always used with a time expression: by then, by that time etc.
to express the speaker’s belief that something has taken place.