世纪金榜 英语 不定式具体运用

世纪金榜 英语 不定式具体运用
世纪金榜 英语 不定式具体运用

世纪金榜 英语 不定式具体运用
一、动词不定时的形式：
肯定式：to do sth 否定式：not to do sth.
被动式：to be done 完成式：to have done
二、动词不定式的用法
1．作主语
A 动词不定式作主语,谓语动词用单数形式.如：
(1) To see is to believe.
(2)To master English gives us much help in the study of sience.
B 不定式或不定式短语作主语时,常用it作形式主语,构成“It is + 形容词(+for sb.)不定式”结构.
It is impossible for him to give up smoking.
2．作宾语
A．动词后直接不定式作宾语的动词有许多,如want,decide,intend,fail,wish,export,pretend,choose等等.
I mean to go there at once.
B.不定式短语作宾语时,如果还带有宾语补足语,往往把不定式短语放在宾补之后,而用it作形式宾语.句型为“主语+find (feel,think,believe,consider,etc) +it+形容词/名词+to do sth”.
I think it necessary to report the thing to the teacher.
I find it interesting to work with him.
C．动词不定式还可以用作介词宾语,但仅限于介词except和but（除了）.
常用句型有：
There is nothing to do but+动词原形
do nothing but+动词（除做….之外别无选择）
can but+动词原形 （只能原形(“只有做……)
have no choice but to do ,只得）
cannot help/choose but+动词原形(不能不……）
3．作表语和宾语不足语
动词不定式作表语,一是主语有不定式充当；二是主语由抽象名词充当.
To teach is to learn.
My job is to help the patient.
【注意】如果在主语中（通常在主语从句或修饰主语的定语从句中）又实意动词do时,作表语的动词不定式省略to.
All I want to do now (What I want to do now) is fill my stomach.
4．作宾语不足语
【注意】在感官动词（see,hear,feel,listen to ,notice,watch,observe等）和使役动词（let,have,make ）后的补足语中,不定式不带to.但这类句子变成被动语态时,必须带to.
I saw him play in the park.
→He was seen to play in the park.
The boss made those men work day and night.
→Those men were made to work day and night.
5．作定语
1、不定式与被修饰的名词往往构成逻辑上的关系.如名词为不定式的逻辑主语,构成主谓关系； 若名词为逻辑宾语,则构成动宾关系；
He is not a man to tell lies.
There will not be enough space to stand in on the earth
2、作定语的不定式与所修饰的名词之间是动宾关系,不定式动词又是不及物动词时,应在该动词上加上一个介词,如;
He has a nice pen to write with.
He is looking for a room to live in.
He is said the best way to travel by is on foot.
6.做状语
不定式作状语时,可表示目的,原因,结果或条件.如;
I’m very glad to hear the news.（原因)
不定式作目的状语时,常可与to,to order to,so as to 连用.
He got up early so as not to be late.\x05
不定式可以跟在表语的形容词之后作状语.
The question is difficult to answer..
有些不定式短语可以做独立成份,通常放在句首,有时置于句中或句未,须用逗号的开.
不定式作结果状语常用如下句型
Too + 形容词/副词 + to do sth
名词/ 形容词/副词 + enough + to do sth
enough+名词 +to do sth
such +（形容词）名词 +as to do sth
so + 形容词/副词 + as to do sth
【注意】不定式作状语,其逻辑主语与句子的主语必须一致.