文档介绍：动词不定式
动词不定式的主要用法
一、动词不定式是非谓语动词的一种形式，在句子中不能独立充当谓语, 没有人称和数的变化。
二、动词不定式是由“to+动词原形”构成(有时可以不带to)。动词不定式的否定形式是“not+动词不定式”
三、动词不定式在句中可作为主语、宾语、表语、定语、状语、宾语补足语，还可与疑问词连用。
主语: 常置于句末, 而用it代替其做形式主语。
It helps you stay fit to go in for sports.
It is dangerous to swim in the deep sea on your own.
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To see is to believe.
To go in for sports helps you stay fit.
It’s important to learn .
一、主语
点击规律: 动词不定式在句中作主语时, 除了直接作主语外，
常放在: It is ＋adj．(形容词)＋to do sth. 或 It is ＋n．(名词)＋to do sth. 句型中, it仅作形式主语。
例: It is easy for me to learn English well.
It’s brave of him to save the girl from water. (me和him分别为句中的逻辑主语)
注: 此句式中不定式逻辑上的主语可由for或of引出, 逻辑主语由of引出时, 表语的形容词为kind，nice, good, polite, clever, foolish, 等表示性格品质评价的形容词。
I want to go home.
The workers demanded to get better pay.
二、宾语
常用动词不定式作宾语的动词有：
hope, refuse, learn, would like
choose, decide, agree, manage,
pretend, plan,fail,offer
I found it necessary to talk to him again.
I found it very difficult to get a job.
think/ consider/ find it + adj.+ to do
形式宾语
like, begin, start等词或短语后面可以接不定式也可以接动名词
点击规律：
这些动词后面除接不定式外, 还可以接动名词, 意思区别不大。
提示板：like doing指经常性动作，而like to do指一次性的动作。
I like swimming，but I don’t like to swim now．我喜欢游泳, 但我现在不想游。
例：stop to do sth. :
停止一件事，去做另一件事。
stop doing sth. :停止正在做的事。
例句：
When the teacher came in, the students stopped talking.
当老师走进来时, 学生们停止说话；
when he came out, the students stopped to talk．
当老师走出去时, 学生们又开始说话。
三、表 语
放在连系动词be后面
例句: His wish is to become a scientist．
Our duty is to protect the environment.
The first important thing is to save the
soldiers’ lives. 当务之急是抢救战士们的生命。
点击规律: 动词不定式在句中作表语时, 通常对连系动词前面的名词进行诠释说明。
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四、定 语
动词不定式做定语放在所修饰的名词 、代词的后面。
例: He is the first person to sail around the world.
I have a lot of work to do．
The doctor said he could do nothing to help the boy．
点击规律: 动词不定式若在句中作定语, 常放在被修饰的名词、代词之后。
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