感官动词后既可跟不带to的不定式作宾补，也可跟v-ing作宾补，前者表示动作的全部过程已结束;后者表示动作正在进行。

I saw him come downstairs.我看见他下了楼。(说明他下楼了这件事)

I saw him coming downstairs.我看见他在下楼。(说明他下楼时的情景)

五。 动词不定式作状语

Later he left home to work in different cities. 不久他离开家到不同的城市工作。

He went to see a football match. 他去看足球比赛了。

In order to catch the other students， I must work hard.

为了赶上其他同学，我必须努力学习。

六。 动词不定式作定语

不定式作定语一般放在所修饰的词的后面。

I need something to eat.

Do you have something to read?

Tom was so excited that he had no word to say.

He is really a fool only to eat.

The man to stand here just now is our English teacher.

The doctor had no way to save the patient.

注意：

(1)作定语的不定式是由及物动词组成，被修饰的名词或代词与不定式之间存在方位或方式关系需要有介词。

I am looking for a room to live in. 我正在找一间住房。(方位关系)

We have many things to do experiments with.

我们有许多做实验的东西(方式关系)

(2)作定语的不定式是由“be + adj + prep”构成的动词短语。

Here there isn‘t any book for me to be interested in.

We have done many things to proud of. 我们做了许多引以自豪的事。

七。 动词不定式作主语

To give is better than to receive.

To reach there on foot is impossible.

动词不定式作主语时，可以用it 代替，把实际主语不定式放在后面。

It‘s better to give than to receive.

It‘s impossible to reach there on foot.

It‘s + adj + for sb. to do sth.

It‘s not difficult for me to study English well.

It‘s easy for him to work out this math problem.

在这个句型中，如果形容词与不定式的逻辑主语关系密切，并且形容词用来说明逻辑主语的性质、品质、特点等，由of引出逻辑主语。这类形容词主要有nice， kind， good， wrong， right等。

八。 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连用，构成不定式短语，可以作主语、宾语、表语、宾语补足语等。

How to do is still a question.

Have you decided when to leave?

九。 动词不定式的否定形式

动词不定式的否定式是在to前加not;不带to的不定式则在动词前加not. 如：

Zhang Ming asked me not to stay at home all day. 张明要我不要整天呆在家里。

My mother let me not do it by myself. 妈妈让我不要独自做这件事。