used to do 过去常常做某事

2、不定式作宾语补足语的动词：

ask sb. to do sth. 请求某人做某事

tell sb. to do sth. 告诉某人做某事

order sb. to do 命令某人做某事。

want sb. to do sth. 想要某人做某事

invite sb. to do sth. 邀请某人做某事

expect sb. to do sth. 期待某人做某事

encourage sb. to do sth. 鼓励某人做某事

advise sb. to do sth. 建议某人做某事

省略to的情况:

使役动词：let, make, have

感官动词：feel, hear, listen to, look at, see, watch, notice

3、动词不定式做主语

动词不定式作主语用的动词不定式常常为it替代，动词不定式（或短语）放在后面。例如：

It is not easy to learn a foreign language.

It took us three days to do the work.

4、动词不定式和疑问词连用

动词不定式可以和疑问词what ,which, how, where, when 等连用，构成不定式短语。如：

I don't know where to go.

He showed me how to use a computer.

What to do is a big problem.

一、请找出下列动词中以动词不定式为宾语的动词并圈出来。

enjoy decide plan spend finish

want practice agree keep need

解析：不定式作宾语口诀：决定想做计划需要同意，

迫不及待下决心做过去常常未能做的事

答案：decide plan want agree need

二、请写出下列动词的合适的非谓语形式填空。

1. Let me ________(help) you water the flowers.

2. I saw him _______(go) into the small store.

3. My mother often asks me _____ (do) some cleaning on Sundays

4. It is kind of you ___ (help) me to carry these books.

5. I want _________________(travel) around the world after graduation.