EXPLANATION ON FUTURE PERFECT

FUTURE PERFECT

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 that something 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 will have cleaned the entire house.
• I won't have finished this test by 3 o'clock.
• Will she have learned enough Chinese to communicate before she moves to Beijing?
• Sam will probably have completed the proposal by the time he leaves this afternoon.
• By the time I finish this course, I will have taken ten tests.
• How many countries will you  have visited by the time you turn 50?

Notice in the examples above 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 time clauses.

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 will continue up until another action in the future.

Examples:

• I will have been in London for six months by the time I leave.
• By Monday, Susan will have had my book for a week.

Although the above use of Future Perfect is normally limited to Non-Continuous Verbs and non-continuous uses of Mixed Verbs, the words "live," "work," "teach," and "study" are sometimes used in this way even though they are NOT Non-Continuous Verbs.

REMEMBER No Future in Time Clauses

Like all future forms, the Future Perfect cannot be used in clauses beginning with time expressions such as: when, while, before, after, by the time, as soon as, if, unless, etc. Instead of Future Perfect, Present Perfect is used.

Examples:

• I am going to see a movie when I will have finished my homework. Not Correct
• I am going to see a movie when I have finished my homework. Correct

ADVERB PLACEMENT

The examples below show the placement for grammar adverbs such as: always, only, never, ever, still, just, etc.

Examples:

• You will only have learned a few words.
• Will you only have learned a few words?

ACTIVE / PASSIVE

Examples:

• They will have completed the project before the deadline. Active
• The project will have been completed before the deadline. Passive

• They will have completed the project before the deadline. Active
• The project will have been completed before the deadline. 

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.