不定词
不定词（to + 动词原型），其身份不再是动词，具有名词、形容词、及副词的功能。
1、名词 用法 ——> 当主词、受词、补语
To buy things in a flea market must be fun.
2、形容词用法——>修饰名词
I have a lot of things to buy.
3、副词用法 ——>表目的、原因等。
· I went there to buy notebooks.
1、不定词当主词
To answer this question is difficult for me
It is diffcult for me to answer this question.
不定词放句首当主词时，视为一件事，其后接单数动词
不定词为首的主词，可以用it代替，
It's kind of you to help me.
It's stupid of you to speak ill of others.
2、不定词当受词
I decided to quit my job
He hoped to be there on time
有些动词，如 decide ，hope ,want, expect ,volunter 等，必须用不定词当受词。
3、不定词当补语（表语）
a、当主语补语 可以放在be动词或连缀动词之后，补充说明主词。
My aim in life is to become a famous singer.
To see is to believe
b、当受词补语， ： 主词 + 动词 + 受词 + 受词补语
He told me to give up smoking
She got he husband to clean up the house.
有些动词，如 want,ask , teach ,tell ,get ,show 等，用不定词当受词补语。
He asked me not to tell her the truth.
4、不定词的形容词用法
不定词当形容词修饰名词或something ....等代名词时，采样后位修饰， 即 ： 名词 / something ... + to + 动词原型
a、修饰名词
1、I have letters to write
2、my mother have a lot of housework to do every day.
b、修饰semethin ..
1、I'll give you something to eat.
2、Do you have anything to read?
They have a lot of things to talk about.
5、不定词的副词用法
不定词可以用来修饰动词，形容词，副词，能够表示目的，原因等
1)、表目的 = in order to + 动词原型
He went to London to study English.
*** go come 通常其后不接不定词，而是and 连接
Come and see me
2) 表原因 ： 跟在表情感的形容词之后
I am glad to see you.
We are sorry to hear the news.
6、含不定词的句型
1、疑问词 + to v ——>此为名词片语，可以当主词，受词，补语。
Which way to go is a bigger problem.
He told me where to take the bus
2、too . . to ..
*** too + {形容词，副词} + to 动词原型
You are too younger to understang the whole thing.
The water is too hotter for me to drink.
He worked too slowly to finish it
3、 ... enough to ...
*** {形容词，副词} + enough to
My younger brother is old enough to go to school.
Bob worded hard enough to pass the exam.