不定式的句法功能
(1)作主语:
To finish the work in ten minutes is very hard.
To lose your heart means failure.
动词不定式短语作主语时,常用it作形式主语,真正的主语不定式置于句后,例如上面两句可用如下形式:
It is very hard to finish the work in ten minutes.
It means failure to lose your heart.
常用句式有:1、It+be+名词+to do。2、It takes sb.+some time+to do。3、It+be+形容词+of sb +to do。4、It+be+形容词+for sb.+to do。常用careless,,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise,等表示赞扬或批评的形容词,不定式前的sb.可作其逻辑主语。
(2)作表语:
Her job is to clean the hall. He appears to have caught a cold.
(3)作宾语:
常与不定式做宾语连用的动词有:want, hope, wish, offer, fail, plan, learn, pretend, refuse, manage, help, agree, promise, prefer, 如果不定式(宾语)后面有宾语补足语,则用it作形式宾语,真正的宾语(不定式)后置,放在宾语补足语后面,只能接不定式做直接宾语的及物动词记忆口诀:
1、 磨豆腐:MERDOWPH:mean, expect, refuse, decide, offer ,wish, pretend, hope
2、 “Who acted Mr. Flp?” W:want,wish,H:help,hope,O:offer,A:agree,arrange,aim,C:choose;E:expect;D:decide,demand,desire;M:manage;R:refuse,F:fail;L:long,learn,P:prevent,promise,plan.
例如: Marx found it important to study the situation in Russia.
动词不定式也可充当介词宾语,如:
I have no choice but to stay here. He did nothing last Sunday but repair his bike.
动词不定式前有时可与疑问词连用,如:
He gave us some advice on how to learn English.
(4)作宾语补足语:
在复合宾语中,动词不定式可充当宾语补足语,如下动词常跟这种复合宾语:want, wish, ask, tell, order, beg, permit, help, advise, persuade, allow, prepare, cause, force, call on, wait for, invite.
此外,介词有时也与这种复合宾语连用,如:
With a lot of work to do, he didn"t go to the cinema.
有些动词如make, let, see, watch, hear, feel, have等与不带有to的不定式连用,但改为被动语态时,不定式要加to,感官使役动词用法口诀:
感使动词真奇怪,to来to去令人猜;
被动句里to回来,主动句里to走开;
动词let要出外, to词可来可不来。 如:
I saw him cross the road.
He was seen to cross the road.
(5)作定语:
动词不定式作定语,放在所修饰的名词或代词后。与所修饰名词有如下关系:
①动宾关系:
I have a meeting to attend.
注意:不定式为不及物动词时,所修饰的名词如果是地点、工具等,应有必要的介词,如: He found a good house to live in. The child has nothing to worry about.
What did you open it with?
如果不定式修饰time, place, way,可以省略介词:
He has no place to live. This is the best way to work out this problem.
如果不定式所修饰名词是不定式动作承受者,不定式可用主动式也可用被动式:
Have you got anything to send? Have you got anything to be sent?
②说明所修饰名词的内容:
We have made a plan to finish the work.
③被修饰名词是不定式逻辑主语: He is the first to get here.
(6)作状语:
①表目的:
He worked day and night to get the money. She sold her hair to buy the watch chain.
注意不定式放句首时,逻辑主语与句子主语要一致:
wrong:To save money, every means has been tried. right:To save money, he has tried every means.
wrong:To learn English well, a dictionary is needed. right:To learn English well, he needs a dictionary.
②表结果: He arrived late to find the train gone.
常用only放在不定式前表示强调: I visited him only to find him out.
③表原因: They were very sad to hear the news.
④表程度:
It"s too dark for us to see anything. The question is simple for him to answer.
(7)作独立成分:
To tell you the truth, I don"t like the way he talked.
(8)不定式的省略:保留to省略do动词。
If you don"t want to do it, you don"t need to.
(9)不定式的并列:第二个不定式可省略to。
He wished to study medicine and become a doctor.