非谓语动词(非限定动词Non—Finite Verbs)
非谓语动词(非限定动词Non—Finite Verbs) 、定义:在句中充当除谓语以外的句子成分的动词形式叫做非谓 语动词。 非谓语动词分为三种形式:不定式(Infinitive)、动名词 (Gerund)和分词(Participle)(分词包括现在分词和过去分词) 二、不定式(一)、不定式的作用 1、作主语:不定式作主语时,谓语用单数。往往用it作形式主语, 把不定式放在谓语后面。如: It took us two hours to finish the job. It is impossible for us to get there on time. It is very kind of you to help us. 注意:(1)其他系动词如look, appear等也可用于此句型。 (2)当不定式作主语的句子中又有一个不定式作表语时,不能 用It is .to.的句型。试比较: It is to negate my own idea to believe him.(错) To believe him is to negate my own idea .(对) (3)It is+ adj. of / for sb. to do sth,结构中,当不定式的逻 辑主语和前面的形容词可以构成系表结构时,用of,否则 用 for. 2、作宾语 (1)动词+不定式。如: He managed to escape from the fire. I find it hard to get along with him. (it 作形式宾语) 注:下列动词通常用不定式作宾语:want, try, hope, wish, need, forget, know, promise, refuse, help, decide, begin, start, learn, agree, choose, get 等 (2)动词+疑问词+to,“特殊疑问句+不定式“相当于名词,作宾语。 如: I don t know what to do next/ how to do it next. I can t decide when to go there. 注意:不定式短语作宾语时,如果还带有宾语补足语,往往把不定 式短语放在宾语补足语之后,用汁作形式宾语。如: I find it necessary to learn a foreign language. 3、作宾语补足语(1)动词+宾语+不定式(tod。)。如: He warned me to be careful. I want you to speak to Tom. What makes you think so?(不带 to 的不定式) 注:可以用动词不定式做宾补的动词有:ask, tell, order ,want ,get, would like, like, advise, invite, allow, help, wish, warn, expect, prefer, encourage (2)表见解、看法的动词结构可为:动词+宾语+ to be的不定式 结构。如: We consider Tom to be one of the best students in our class. The book is believed to be useful.(被动语态) (3)There +不定式。如: We didn t expect there to be so many people there. 我们没料到会有那么多人在那里。 注意:(1)有些动词需用as短语作补语,像regard, think, believe, take, consider。如: We regard Tom as our best teacher. 我们认为汤姆是我们最好的老师。 Mary took him as her father. 玛丽把他当作自己的父亲。 (2)在动词 feel (一感),hear, listen to (二听),have, let, make (三让),notice, see, watch, observe, look at (五看)(即: 吾看 三室两厅一感觉)等后面的补足语中,不定式不带t。,但变为被动语 态后,必须带to。如: They saw the boy fall off the tree. The boy was seen to fall off the tree. (3)help后面作宾语补足语的不定式可以带t。,也可以不带to. I often help him (to) clean the room. I helped him (to) find his things. 4、作定语 不定式作定语,修饰名词或代词,不定式和它所修饰的 名词之间有逻辑上的主谓关系、动状关系、同位关系或动宾关系。不 定式通常要放在这些被修饰的词后。如: I have a lot of work to do.(动宾关系) He is looking for a room to live in,(动状关系) He is the first person to think of the idea.(主谓关系) He has got a chance to go abroad.(同位关系) 注意: (1) .不定式的逻辑主语是句子的主语时,不定式用主动形式表被动。 如: Do you have anything else to say? (2) .如果作定语的不定式是一个短语,则要保留不定时短语中的副 词或介词。如: I need a pen to write with . (I will wirte with the pen )(我需要一直钢笔写字) I have a little baby to look after . (I must look after the little baby )(我有一个婴儿要照看) 5. 作状语,表示目的、结果、原因等,有时还有一些固定搭配的不定 式短语,如 in order to , so as to, so.as to, such .as to, enough to, too.to 等。 (1) 做目的状语,to, only to (仅仅为了),in order to, so as to, so(such)as to.(如此…以便…)如: He ran so fast as to catch the first bus. 他飞快地跑以便赶上第一班车。 He came to the school to see his son. (2) 作结果状语,表事先没有预料到的,要放在句子后面。如: He hurried to the post office only to find it was closed. He searched the roo