Future Perfect

FORM Future Perfect with "Will"

[will have + past participle]

Examples:

You will have perfected your English by the time you come back from the U.S.

Will you have perfected your English by the time you come back from the U.S.?

You will not have perfected your English by the time you come back from the U.S.

FORM Future Perfect with "Be Going To"

[am/is/are + going to have + past participle]

Examples:

You are going to have perfected your English by the time you come back from the U.S.

Are you going to have perfected your English by the time you come back from the U.S.?

You are not going to have perfected your English by the time you come back from the U.S.

NOTE: It is possible to use either "will" or "be going to" to create the Future Perfect with little or no difference in meaning.

Complete List of Future Perfect Forms

USE 1 Completed Action Before Something in the Future