The Future Perfect

1. Completed actions in the future

We use the future perfect to describe an action which​​ will be completed​​ in the future.

It is common to use​​ by + a time reference: by​​ January, by​​ 2035, by next month, by the time you arrive.

 I​​ will have cleaned​​ the whole house by the time your parents arrive.

 We​​ will have arrived​​ by 4pm.

 They​​ will have built​​ the bridge by next year.

2. With for

We often use ‘for’ with the future continuous to talk about​​ the duration​​ of a future activity.

 By next month, I​​ will have lived​​ here​​ for two years.

 They​​ will have been married for 40 years​​ by the end of this year.

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3. Assumptions

We can use the future perfect to express​​ assumptions​​ about​​ the past or​​ the present.

 As you​​ will have heard, we will be changing office.​​ (I am quite confident that you have heard it)

 He​​ will have woken up​​ by now – it’s 10 o’clock.​​