3-41. Выражение вероятности

 
Как и все модальные глаголы (кроме shall) will может употребляться, чтобы выразить предположение о настоящем (весьма сильную уверенность):

There's somebody at the door. That'll be the postman.
That will be the postman, I expect.
There's somebody coming up the stairs. – That'll be Mary.
As I'm sure you will understand, we cannot wait any longer for our order.
Don't phone them now – they'll be having dinner.
Don’t phone Ann now. She’ll be busy.
This will be the book you're looking for.
You will have heard the news.

Will+have+past participle выражает такое же предположение в отношении прошлого:

Dear Sir, you will recently have received a form ...
We can't go and see them now – they'll have gone to bed.
As you will have noticed, he's got new glasses.
Most people won't have seen last night's lunar eclipse.