S + will have + V3/ed
Action completed before a specific future time.
Often with by + time; expectations about completion.
I will have finished the report by Friday.
Tôi sẽ hoàn thành báo cáo trước thứ Sáu.
They will have left by the time you arrive.
Họ sẽ rời đi trước khi bạn đến.