初三英语上册知识点(全)

初三英语上册知识点(全)

语法复习

动词不定式

一.定义：

由to+动词原形构成。不定式是一种非限定性动词。而非限定动词是指那些在句中不能单独充

当谓语的动词，可分为不定式，动名词，现在分词和过去分词。动词不定式”由动词+不

定式构成。动词不定式在句中可以作句子除谓语之外的任何句子成分。动词不定式的被动形式除了一般形式外还有其完成式和进行式。

二.动词不定式的构成: to+动词原形

作主语

动词不定式作主语时，句子的谓语动词常用单数，其位置有以下两种: 式置于句首。女口：To get there by bike will take us half an hour.

把真正的主语不定式置于句后，常用于下列句式中。如：

(1)把不定

(2)用it作形式主语，

① It+be+ 名词+to do It's

our duty to take good care of the old. ② It takes sb+some time+to do How long did it take you to finish the work? ③ It+be+ 形容词+for sb+to do It is difficult for us to finish writ ing the compositi on in a quarter of an hour. ④ It+be+ 形容词+of sb+to do

等也可用于此句型 (2)不定式作为句子成分时，

动词用单数形式。

It is to 的句型

(对)To see is to believe. 眼见为实。 (错)It is to believe to see.

三. 动词不定式作宾语

It is stupid of you to write seems(appears)+

形容词 +to do

常用表示客观情况的形容词，如： down everything (that) the teacher says. ⑤ It

在句型③中，

等；

It seemed impossible to save mon ey.

difficult,easy,hard,importa nt,impossible,

necessary 在句型④中，常用 careless,clever,good,foolish,h on est,ki nd,lazy, nice,right,silly,stupid,wise

等 表示赞扬或批评的词。在不定式前的

sb ，可看作其逻辑主语。这一句式有时相当于

Sb

is+ 形容词 +to do 句式 ， 女口 : It's kind of you to help me with my English.= You are kind to

我做这事太容

helpme with my En glish.

易了

(3)举例

(1)

It's easy (for me) to do that.

easy, difficult, hard,

importa nt,

possible, impossible, comfortable,

n ecessary, better; not eno ugh

the first, the n ext, the last,

It's so nice to hear your voice.

the best, too much, too little, 听到你的

声音真高兴。

It's

n ecessary for you to lock the car whe n you do not use it. 必要的。

(2) It's very kind of him to help us.

当你不用车的时候， 他帮助我们，他真好。

锁车是有

Kind, ni ce, stupid, con siderate( rude, clever, 考虑周到的),

foolish,

believe him. anything.

silly, selfish( 我们真愚蠢，竟然相信了他。

他不给他们任何东西，这显得太自私了。

thoughtful, thoughtless,

自私的) 例句:

It was silly of us to

brave,

It seemed selfish of him not to give them

注意：(1)

其他系动词如，

look ，appear

(3)当不定式作主语的句子中又有一个不定式作表语时，不能用

后面能接不定式作宾语的动词有: agree, ask, choose, decide, forget, hope, lear n, want,

wish, would like 等。

We hope to get there before dark. 我们希望天黑以前到那儿。

The man decided to do it herself. 那个男人决定自己做那件事。

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

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 wa nt both of you to go. 我要你们俩去。