e +动词不定式（即be + to do sth.）的用法如下：
1.表示按计划或安排要做的事.例如：
When are you to leave for home?你什么时候回家?
She is to be married next month.她将于下个月结婚.
The Queen is to visit Japan in a week’s time.女王将于一周后访问日本.
这种结构也可用于过去.was / were to do sth.表示曾经计划要做的事,但不表明计划是否被执行,或表示“命运（即命中注定要发生的事）”,而非计划；was / were to have done sth.表示未曾实现的计划.例如：
I felt nervous because I was soon to leave home for the first time.我感到很紧张,因为我很快就要首次离开家了.
They said goodbye,little knowing that they were never to meet again.他们告了别,不知道以后再也不会见面了.
We were to have told you,but you were not in.我们本来想告诉你的,但是你不在家.