Обозначает действие, которое совершится до определенного момента в будущем.
•By next November, I will have received my promotion.
•By the time I finish this course, I will have taken ten tests.
Часто употребляется с предлогом by: by the end of the year, by 5 o'clock, by that time и т. д.
б) Если момент времени выражен другим будущим действием, то употребляются предлоги before до того как, и when когда:
•Will she have learned enough Chinese to communicate before she moves to Beijing?
•I’ll have read the book before we meet.
Примеры употребления времен группы Perfect:
•Jack and Sandra have been married for 14 years. (present perfect)
•Next year the will have been married for 15 years. (future perfect)
•When their first child was born, they had been married for three years. (past perfect)
Чаще всего время, к которому завершится действие, известно или понятно из контекста