By the end of next week he will be back.改错.
问题描述:
By the end of next week he will be back.改错.
答
By 改成 At
答
By the end of next week, he will have been back.
答
By the end of next week,he will have been back.是这句,因为by the end of nest week是一个表将来完成时的时间状语,所以主句应用将来完成时.若有不解,请看语法中关于动词的时态与语态一章.