1. Future Perfect will + have + verb (past participle)
By the time we get to the movies, the film will have already started.

2. Use Future Perfect
to talk about a completed action or event in the future / to look back from the future to an earlier event, often with BY or BY THE TIME.
By June, he will have payed his debt.

3. By May, she will have bought a car.
She’ll have looked at a lot of cars by then.

4. Work in pairs
A: Have you repaired the bike yet?
B: No, I will have repaired it by Monday.
Have you sent the letter yet? No/ by Sunday.
Have you done the homework yet? No/ by Friday.
Have you bought the book yet? No/ by Saturday.
Have you read my story yet? No/ by the end of the week.
Have you sold the car yet? No/ by May.
Have you told Mary about us? No/ by Tuesday.
Have you found the box yet? No/ by the end of March.
Have you built the house yet? No/ by November.