be+动词不定式即be+to do sth
1表示按计划或安排要做的事
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。
注意：这种结构也可使用于过去时的句子。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。如：
I felt nervous because I was soon to leave home for the first time.
我感到很紧张，因为我很快就要第一次离开家了。
2表示“应该”，相当于should，ought to 。如：
You are to report to the police.你应该报警。
3 表示“必须”，相当于must, have to。如
You are to do your homework before you watch TV.看电视之前你得先做完作业。
4 表示“想，打算”，相当于intend, want。 如：
If we are to be there before ten, we’ll have to go now.
如果我们要在十点前到，我们现在就得走。
5 用于第一人称疑问句，表示征求对方意见。如：
What are we to do next?我们下一步该怎么办？
6用于否定句，表示禁止，相当于mustn’t。 如：
You are not to smoke in the reading room.你不可以在阅览室吸烟。
7 表示“可以，可能”，相当于may,can。如：
The news is to be found in the evening paper.这条消息可以在晚报上见到。
8 were to do sth用于 if或even if/though 从句中，表示对未来假设。如
If I were to tell you that I passed the exam, would you believe me?
要是我告诉你我及格了，你会相信吗？
9 be to blame（该受责备，对某坏事应负责任）和be to let（待出租）两种结构中，用不定式的主动形式表示被动含义。如：
Which driver is to blame for the accident?这事故是哪个司机的责任？
10 be going to
1）表示将要发生的事情或打算最近要进行的动作。如：
It is going to rain soon.快要下雨了。
2）在含有条件状语从句的主从复合句中，主句一般不用be going to，而常用will（第一人称用shall）。如
The football match will be put off if it rains tomorrow.如果明天下雨，足球赛将被推迟举行。
11 be about to
1）表示即将发生的动作，在时间上指最近的将来。
The new school year is about to begin. 新学期开学在即。
2）在含有be about to的句子中，不能再加时间状语。如：
错误 The medical team is about to start immediately.
正确 The medical team is about to start.医疗队就要出发了。
习题
1 I ____ to bed when there was a knock at the door.
A went B is to be sent C was to go D. was about to go
2 -___we ____ again next week? -Yes, le’s make it next Wednesday.
A are, to meet B. Shall, be to meet C. Will, meet D. Are, meeting
3 As students, we _____.
A. won’t smoke. B. are not to smoke C aren’t smoking D don’t smoke
4 Who do you think ____ for the failure of their marriage.
A to blameB.to be blameC.is to blame D. is to be blamed
5 Look at these clouds. _________,
A It’s going to rain B. It’s raining C It is to rain D. It can rain
6 Neither you nor he ______ to the front.
A are to be sent B. is to be sent C. have to be sent D.is to be sent
7 If the sun ______ tomorrow, what would we do?
A were not to raise B. does not rise C. would not rise D. were not to rise
8 -We just saw John at the bookstore.
-That’s strange examination _____ early July.
A will come B. was to come C. is coming D. is to come
e 9 The final examination _______ early July.
A. is to be held B. is to be taken place
B. is going to holdD. will be to take place
10 A new hospital was to____ in this district, but the money wasn’t collected yet.
A have been built B. be built C. built D have built
答案1 D 2 A 3B 4 C 5 A 6B 7D 8B 9A 10A
