Краткое объяснение - Short Explanation

Future Perfect Continuous (Progressive)
Будущее совершенное продолженное
USE & FORM **

will + have been doing

Утверждение I, we shall/will (‘ll) have been doing .
You, he, they will have been doing.

Вопрос Will I, we have been doing ?
Will you, he, they have been doing?

Отрицание I, we shall/will not have been doing here.

You, he, they will not have been doing.

I will have been doing this work for 3 years by September. – Will you have been doing this work for 3 years by September? – I won’t have been doing this work for 3 years by September.

Случаи употребления:
1.Действие, которое длилось в прошлом некоторый период времени и в определенный момент в будущем будет еще в процессе.

She’ll have been living in Paris for ten years by next month.
How long will your son have been learning Spanish by then?
The client won’t have been staying in this hotel for long by tomorrow.