动词不定式用法.docx

动词不定式用法
动词不定式用法
 
不定式由“to + 动词原形”构成,其否定形式是“not to + 动词原形”。不定式可以带宾语或状语构成不定式短语,没有人称和数的变化,但有时态和语态的变化。不定式可作主语、宾语、状语、表语和定语,但不能单独作谓语。不定式的逻辑主语有时有“for + 名词或代词宾格”构成。

1)作主语。不定式短语作主语时,往往放在谓语之后,用it作形式宾语。如:
To see is to believe.
It is right to give up smoking.
 
2)作宾语。不定式短语作宾语时,如果还带有宾语补足语,往往把不定式宾语放在宾语补足语之后,而用it作形式宾语。如:
He wanted to go.
I find it interesting to study history.
有些动词后只能用动词不定式作宾语,必须跟动名词。如:decide,plan,desire,expect,hope, wish,pretend,promise,refuse,afford,agree,ask,fail,tend,pretend,manage
 
3)作宾语补足语。如:
He asked me to do the work with him.
注意:在feel,hear,notice,observe,see,watch,have,let,make等词后的补足语中,不定式不带to。但这些句子如果变成被动结构时,就必须带to。如:
I often hear him sing the song.
He is often heard to sing the song.
注意:动词不定式在介词but后面时,如果介词之前有行为动词do的各种形式,那么,这些介词后的不定式不带to,否则要带to。另外,在can’t choose but和can’t help but等后面的不定式也省略to。如:
She could do nothing but cry.
I have no choice but to go.
 
4)作定语。如:
I have some books for you to read.
①作定语的不定式如果是不及物动词,或者不定式所修饰的名词或代词是不定式动作的地点、工具等,不定式后面须有相应的介词。如:
He is looking for a room to live in.
There is nothing to worry about.
Please give me a knife to cut with.
但是,不定式所修饰的名词如果是time,place或way,不定式后面的介词****惯上省去。如:
He had not money and no place to live.
②当作定语的不定式所修饰的名词或代词是不定式动作的承受者时,不定式既可以用主动语态,也可用被动语态,但其含义有所不同。试比较:
Have you anything to send ?
(你有什么东西要寄吗?——不定式to send的动作执行者是“你”)
Have you anything to be seat.
[你有什么要(我或别人)寄的东西吗?——不定式t