By next Sunday she ( )with us for three weeks.A.will have st
3个回答

将来完成时

1.概念:在将来某一时刻之前开始的动作或状态

2.时间状语:by the time of;by the end of+时间短语(将来);by the time+从句(将来)

3.基本结构:be going to/will/shall + have done

4例句:By the time you get back,great changes will have taken place in this area

先A

has 跟在be going to will shall 后面变动原形即have