发布时间 : 星期一 文章非谓语动词之不定式讲义更新完毕开始阅读f3d9e45adcccda38376baf1ffc4ffe473268fd64
非谓语动词之不定式讲义
一、分析下面例句的结构
I decide to study hard.
二、动词不定式的构成
不定式的基本形式： to+ 动词原形， 有时可以不用to。 这里的to是不定式符号，本身无词义。动词不定式的否定形式是“not (+ to) + 动词原形”。
不定式具有动词的特点，即可以有自己的宾语和状语，但它没有人称和数的变化 1.不定式作主语
不定式作主语，谓语动词用第三人称单数 To speak English is not easy for us.
To get there by underground will take a whole day..
为了保持句子平衡，常常用it作形式主语，而把不定式放在后面 常见的结构有：①It be + adj （+ for/of）+ 动词不定式
It is very important for us to protect the environment. ↓
(表示事物或动作性质) It is very clever of to do it like that. ↓
(表示人的品质、特征)
②It takes/took sb + 时间 + 动词不定式
It takes me an hour to finish my homework. ③It is + 名词 + 动词不定式
It is my honor to give the speech for you.
2.不定式作宾语
(1)一些谓语动词后只能用不定式作宾语，常见的这类词是表示命令、打算或希望的，如would like, want, wish, hope, decide, plan, expect等 Would you like to see a film this evening? I hope to achieve my dream in the future.
(2)在find, think后跟不定式作宾语时，常用it做形式宾语， 而将真正的宾语放在后面 I find it easy to read English every day. 3.不定式作表语
（1）一般情况，不定式作表语，起到对主语中心名词性质和内容的一个说明
My aim is to get the first place.
His idea is to climb the mountain from the north.
（2）当主语和表语都是不定式时，其含义往往是主语是条件，表语是结果，如: To be kind to the enemy is to be cruel to the people. To do that would be to cut the foot to fit the shoe. 3.不定式作宾语补足语
宾语补足语有些及物动词，接了宾语意义仍不完整，还需要有一个其他的句子成分来补充说明宾语的状态、意义等。放于宾语之后。 不定式作宾语补足语时与宾语有逻辑上的主谓关系 Lucy asked him to turn down the radio.
tell, ask, want, get, would like ,encourage 后常跟动词不定式作宾补
注意：在make,let, see, hear, watch等使役、感官动词后，不定式省略to(但在被动语态中不能省略)
The boss made them work the whole night.
=They were made _______ the whole night by the boss. 4.不定式作定语
（1）不定式作定语时，应放在名词之后。它与名词有逻辑上的被动关系。 Do you have some food to eat?
（2）如果是不及物动词，且与所修饰的词之间有被动关系，要在不定式后加上适当的介词 There is nothing to worry about.
5.不定式常和疑问词what, which, when, where, how连用，相当于一个宾语从句 The teacher is telling the students what to do.(what to do =what they should do) 6.不定式作状语
动词不定式作状语用来修饰动词、形容词、副词或整个句子，通常表示目的、原因、结果等。 （1）表示目的
They ran over to welcome the delegates. 常用结构有： A.in order to
I went to the post office in order to mail a letter. B.so as to
We had better start early so as to catch the train. （2）表示结果 A.so ... as to ...
Would you be so kind as to lend me your bicycle?
B.such... as to ...
I’m not such a fool as to believe that. C.enough to
The boy is old enough to go to school. D.too...to...
The box is too heavy to carry.
当too 前面有only时， only too ... to 译为肯定 I am only too pleased to help you.
当不定式前有表否定意义的词时， 译为肯定 We are never too old to learn.
He is too smart not to see your point.(很...所以不会不....) E.only to do 表示一种意想不到的或者不愉快的结果 We went to the train station only to find that the train had left. （3）表示原因
不定式在某些形容词后表示喜怒哀乐的原因 I am so sorry to hear the bad news.
易错点注意：1.不定式和含有介词to的固定短语的区别
遇到下列短语注意，其中的to是介词，后面加名词、代词或动词ing make a contribution to devote ...to... look forward to ... prefer..to.. get/be used to... pay attention to ...
2. 在某些句型中，当主语部分有动作动词do时，作表语的不定式可以省略to，如： All we have to do is push the button.
The only thing I can do now is go on by myself.
3.but 连接的前后两个动作，如果前面有动作动词是do则后面动作用省略to的不定式；如果前面没有动作动词do则后面动作用含to的不定式，即有do无to，有to无do。 He had no choice but to pay the bill. She could do nothing but stand and wonder