Ingles

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 thetime 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 + pastparticiple]
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 arenot 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 differencein meaning.

USE 1 Completed Action Before Something in the Future

The Future Perfect expresses the idea that something will occur before another action in the future. It can also show thatsomething will happen before a specific time in the future.
Examples:
By next November, I will have received my promotion.
By the time he gets home, she is going to have cleaned the entire house.
Iam not going to have finished this test by 3 o'clock.
Will she have learned enough Chinese to communicate before she moves to Beijing?
Sam is probably going to have completed the proposal by thetime he leaves this afternoon.
By the time I finish this course, I will have taken ten tests.
How many countries are you going to have visited by the time you turn 50?
Notice in the examplesabove that the reference points (marked in italics) are in Simple Present rather than Simple Future. This is because the interruptions are in time clauses, and you cannot use future tenses in timeclauses.
USE 2 Duration Before Something in the Future (Non-Continuous Verbs)

With Non-Continuous Verbs and some non-continuous uses of Mixed Verbs, we use the Future Perfect to show that something...