初三英语语法知识点：动词不定式
语法的学习，对于学生来说有着重要的意义。下面是小编收集整理的初三英语《动词不定式》的语法复习知识点以供大家学习。
初三英语语法知识点：动词不定式
一. 定义：
动词不定式是非谓语动词的一种，它没有人称和数的变化，在句子中不能独立作谓语，但它仍保持动词的特点，既可以有自己的宾语和状语。同时动词不定式又具有名词、形容词、副词的特征，在句中可以作主语、表语、宾语、宾语补足语、定语和状语。
二. 动词不定式的构成：to+动词原形
三. 动词不定式作宾语
后面能接不定式作宾语的动词有：agree, ask, choose, decide, forget, hope, learn, want, wish, would like等。
We hope to get there before dark. 我们希望天黑以前到那儿。
The girl decided to do it herself. 那个姑娘决定自己做那件事。
动词不定式作宾语的注意事项(2点)
1. 有些动词既可跟不定式作宾语，也可跟动名词作宾语，但含义不同： remember to do 记住要做某事
remember doing 记得曾经做过某事
forget to do忘记要做某事
forget doing 忘记曾经做过某事
stop to do 停下来去做某事
stop doing 停止做某事
go on to do 继续做另一件事
go on doing 继续做原来在做的事
I remember seeing you somewhere before.
我记得以前在哪儿见过你。
Please remember to turn off the light when you leave.
离开时请记得关好灯。
2. 不定式作宾语时，如带有宾语补足语，则要把不定式放到后面，用it作形式宾语，构成“主语+动词+it+宾补(形容词、名词)+不定式”结构。
如：He found it very difficult to get to sleep.
他发现很难入睡。
四. 动词不定式作宾语补足语
1. 后面能接to不定式作宾语补足语的动词有：ask, order, teach, tell, want, wish, help等。
The teacher told us to do Exercise 1. 老师要我们做练习一。
I want both of you to go. 我要你们俩去。
We helped her (to) repair her bike. 我们帮助她修理自行车。
2. 使役动词let, have, make及感官动词see, watch, notice, hear, feel等要以不带to的不定式作宾补。
Let’s have a rest. 我们休息一会吧。
I saw him come in. 我看见他进来了。
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?