动词不定式
1、作主语
To learn a foreign language is not easy.
It is not easy to learn a foreign language.
2、作宾语
They began to read.
3、作宾语补足语
Jim asked me to help him with his lessons.
We often heard her sing.
4、作定语
I have an important meeting to attend.
5、作状语
She went to see her grandma yesterday.
6、用在how, when, where, what, which等之后
I don’t know how to use a computer.
Do you know when to start?
He didn’t know what to do next.
