简介
1.不定式定义:
不定式是一种非限定性动词。而非限定动词是指那些在句中不能单独充当谓语的动词,可分为不定式,动名词,现在分词和过去分词。
2.用途:
在句中不能作谓语。它具有动词的性质,本身可以带宾语和状语。
3.形式:
动词+不定式:由to+动词原形构成。
动词不定式在句中可以作句子任何成分。动词不定式的被动形式除了一般形式外还有其完成式和进行式。
作定语
⒈不定式作定语
不定式在句中作定语,置于被修饰的名词或代词之后。如:
①The next train to arrive is from Washington.
②Do you have anything to be taken to your sister?
③Do you have anything to say on the question?
④Would you please give me some paper to write on?
⑤My wish to visit France has come true at last.
不定式短语作定语和被修饰词之间表示以下关系:
(1)表示将来的动作(例①)。
(2)与被修饰词之间有动宾关系,如是不及物动词,则需加介词(例④)。
(3)与被修饰词之间有动宾关系,同时与句中其它词之间又有逻辑上的主谓关系时,尽管有被动含义,却仍用主动语态(例③);如只有动宾关系,而无逻辑上的主谓关系,则需用被动语态(例②)。
(4)不定式作定语时,一般可转换为定语从句,例①to arrive=that will arrive。
进行式
形式
to be +现在分词
He seems to be following us.
他好像在跟着我们。
用法
①用于助动词之后
He must be coming by bus.
他一定是乘公共汽车来的。
You shouldn't be reading a novel.
现在你不应该看小说,你应该看课本。
②用于apprar,happen,pretend,seem之后
I happened to be standing next to him when he collapsed.相当于:
It happened that I was standing next to him when he collapsed.
他倒下的时候我恰巧站在他身边。
③hope和promise之后,或agree,arrange,decide,determine/be determined,plan,undertake之后,但用于hope和promise后更常见:
I hope/hoped to be earning my living in a year's time.相当于:
I hope I will/I hoped I would be earning……
我希望在一年之内能自食其力。
完成进行式
形式
to have been +现在分词
He seems to have been spying for both sides.
他似乎一直在为两方面搞秘密情报。
用法
只要用于助动词之后和appear,seem之后,但也可以用在happen,pretend以及believe,know,report,say,understand的被动式之后:
He appears to have been waiting a long time.相当于:
It appears that he has been waiting a long time.
看来他已经等了很久了。
He pretended to have been studying.相当于:
He pretended that he had been studying.
他假装一直在学习的样子。
句型用法
在There be句型中的动词不定式:
For example one,There are too much homework to write.
two,There are students writing too much homework.