一 作主语 To see is to believe.
1. It be adj. \ n. to do sth.
It’s good to see you.
It’s difficult to learn maths well.
2. It takes sb. some time to do sth.
1 跳舞非常有趣。To dance is a lot of fun.=
2 种些植物是非常有必要的。To grow plants is very important.=
3 说英语对我来说并不容易。To speak English is not easy for me.=
4 听到你的声音真高兴。To hear your voice is so nice.=
二 作表语
To see is to believe.
他的愿望是成为一名医生。His wish is to be a doctor.
1 我的工作是每天打扫这间屋子。
My work is to clean the room every day.
2 最上策的计划就是马上离开这儿。
The best plan is to leave at once.
3 我的梦想就是成为一名科学家。My dream is to be a scientist.
三 作宾语 (v. + to do )
I want to buy a computer.
She hopes to find a better job.
I wish to go with you.
need to do learn to do agree to do
plan to do decide to do refuse to do
begin to do start to do try to do
forget to do remember to do like to do
stop to do go on to do
1 他想借用我的录音机。He wants to borrow my radio.
2 他们开始读和写。They began to read and write.
3 李琳喜欢玩什么？她喜欢踢足球。What sports does Li Lin like to play? She likes to play soccer.
4 你长大了想做什么？What do you want to be when you grow up?
四 作宾语补足语：(v. + sb. + to do )
She asked me to help her.
The teacher told him to come on time.
Edison’s mother taught him to read and write.
want sb to do wish sb to do
get sb to do order sb to do
find sb to be like sb to do
would like sb to do help sb （to） do
1 他要求我再大声点儿。She asked me to speak louder.
2 Lucy告诉他不要哭。Lucy told him not to cry.
3 吉姆告诉李明由衷地祝福每个人。Jim told Li Ming to give his best
wishes to everybody.
4 他让我再做一次。He let me do it again.
作宾语补足语不带to 的情况：
Let him do it.
I saw him cross the street.
常见动词有：
使役动词: let, make, have
感官动词: see, watch, hear, feel, listen to
比较： I heard her singing in the next room when I came in .
I heard her sing in the next room last week.
五 作状语 (adverbial)：
He came to show me his new CD player. (目的)
I went there to see my teacher. (目的)
She came back to get her English book. (目的)
The boy was too frightened to move. (结果)
I am glad to see you. （原因）
I’m sorry to trouble you. （原因）
六 作定语(后置)
Have you get anything to say?
He’s looking for a room to live in?
She has no clothes to wear?
（这时不定式与被修饰词有动宾关系。若是不及物动词，介词不能省略）
Give me something to drink.
I have two books to read.
They have much food to eat.
He asked for a room to live in.
I don’t have a pen to write with.
The ice is hard to skate on.
He bought a toy to play with.
1 我有许多书要看。I have many books to read.
2 她有几个问题要问。She has a few questions to ask.
3 他有一台电视要修。He has a TV set to repair.
4. 我没什么可担心的。I have nothing to worry about.
5．他是一个值得信赖的人。He is a man to believe in.
6 爱迪生是第一个发明电灯的人。Edison was the first man to invent the lights.
7 他那生病母亲最多可活三个月。His sick mother has three months to live at most.
七 不定式与疑问词连用
常用动词有: ask know learn teach tell understand等。
疑问词who, what, which, where, when, how
加to do可构成不定式短语，在句中可用作主语、
宾语、宾语补足语、表语等。
When to start has not been decided.
I don’t know what to do.
He can tell you where to get the book.
The question is who(m) to ask.
构成形式 作用 例 句
who
what
which
how 等＋to do
where
when 主语 When to start has not been decided.
表语 The question is where to go.
宾语 I don’t know how to do.
宾补 Nobody told us what to do.
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