1、动词不定式动名词用法及介词的用法动词不定式、动名词用法要点讲解 一、作主语 不定式作主语 动词不定式作主语时，句子的谓语动词常用单数，其位置有以下两种： (1)把不定式置于句首。如： To get there by bike will take us half an hour. (2)用it作形式主语，把真正的主语不定式置于句后，常用于下列句式中。如： Itbe名词to do Its our duty to take good care of the old. It takes sb+some time+to do How long did it take you to finish the
2、work? Itbe形容词for sbto do It is difficult for us to finish writing the compositionin a quarter of an hour. Itbe形容词of sbto do It is stupid of you to write down everything the teachersays. It seems(appears)形容词to do It seemed impossible to save money. 在句型中，常用表示客观情况的形容词，如：difficult, easy, hard, important
3、, impossible, necessary 等；在句型中，常用careless, clever, good, foolish, honest, kind, lazy, nice, right, silly, stupid, wise等 表示赞扬或批评的词。在不定式前的sb，可看作其逻辑主语。这一句式有时相当于Sb is形容词to do句式 ，如：Its kind of you to help me with my English.=You are kind to help me with my English. 动名词作主语 Learning without practice is no
4、good. 动名词作主语时，也常用It句式。如： Its +no good(no use,fun,a pleasure,a waste of time)+doing Its no good reading in dim light. Its no use sitting here waiting. Its形容词doing Its dangerous swimming in the sea in windy days. 这样用的形容词有expensive,nice,tiring等，但important, necessary则不适用于这种结构，应用不定式 代替，如：Its important fo
5、r you to keep fit. There is no+doing There is no saying what will happen next. 在这一结构中，动名词后常带宾语，相当于Its impossible to结构。 动词不定式和动名词作主语的区别 不定式作主语经常表示具体动作，常与特定的动作执行者联系在一起；而动名词作主语经常表示抽象动 作，经常不与特定的动作执行者联系在一起。如： Its no good eating too much fat. Its no good for you to eat so much fat. 动名词结构作主语，可以用名词或代词属格形式作逻
6、辑主语。如： Its no use your pretending that you didnt know the rules. 二、作宾语 不定式作宾语 以下动词后，只能跟不定式作宾语。如：agree, ask, aim, arrange, choose, decide, demand, expect, fail , help, hope, lean, long, manage, offer,plan,prepare,pretend,promise,refuse,wish等，这些词大部分可接th at引导的从句。如： I decided to ask for my money back. I
7、 decided that I would ask for my money back. When our visit to the farm was over,we expected to startback on foot. When our visit to the farm was over, we expected that wewould start back on foot. 当复合宾语中的宾语是不定式时，先用形式宾语it代替不定式，把不定式置于补语之后，即：主语动 词it补语to do句式。如:We think it quite important for us to lear
8、n a foreignlanguage well. He feels it his duty to help the poor. 介词but,except,besides+to do(do) 在这种句型中，如介词前有动词do，后面应接不带to的不定式；如无do，则接to不定式，即带do不带to， 带to不带do。如： The enemy soldiers had no choice but to give in. On Sunday afternoon I had nothing to do but watch TV. 动名词作宾语 以下动词后，只能接动名词作宾语，如：admit, appre
9、ciate, consider, delay, enjoy, finish, keep, imagine,mind,miss,practise,resist,risk,save,suggest,dont mind,give up,insist,on, put off等。如： I suggest spending our summer vacation in a seaside town. You must give up smoking, for it does too much harm toyour health. 动名词作介词的宾语 I should go to attend the b
10、irthday celebration instead of staying at home. What about inviting Li Jun to make a speech? 动名词前的介词有时可以省略，如：have difficulty(in)doing,have no trouble(in)doing, lose no ti me(in)doing, prevent/stop(from)doing,there is no use(in)doing等。 部分动词后面，既可接动词不定式，也可接动名词作宾语，意义不变。如：begin,continue,start,hate,like,l
11、ove,need,require,want等。 在need,require,want后接-ing形式，表示被动意义，也可接不定式，但要用被动形式，如：Your handwr iting needs improving(tobe improved). hate,love,like接不定式表示特定的未来事件，接动名词表示目前 正在进行的活动或一般的行为。 在下列情况下，一般要用不定式： hate,like,love前有would(should)时，如：Id like to have a cup of coffee. 当谓语动词begin,continue,start等是进行式时，如：Thestud
12、ents are starting to work on the di fficult maths problem. begin,continue,start与know,understand等状态动词连用时，如：I soon began to understand what was happening. advise,allow,encourage,forbid,permit等动词后接动名词作宾语，或带不定式作宾语补足语。如： Our teachers dont permit our swimming in the lake. Our teachers dont permit us to sw
13、im in the lake. 部分动词后接不定式或动名词时，意义差别较大，应根据句子语境选择使用。 forget,remember,regret后接不定式，表示现在或未来的动作，接动名词表示动作已经发生。如： Dont forget fo post the letter for me. Have you forgotten meeting her in Beijing Airport? Remember to close the windows before you leave. I remember writing him a letter a year ago. We regret to
14、 tell you that all of you are not invited toattend the meeting. They regretted ordering these books from abroad. mean to do 打算做某事 doing 意味着 I meant to catch up with the early bus. This means wasting a lot of money. try to do 设法尽力做某事 doing 试着做某事 You should try to overcome your shortcomings. Try worki
15、ng out the physics problem in another way. stop to do 停下一件事去做另一件事（不定式作目的状语） doing 停止做某事 On the way to the airport,I stopped to buy a paper. Youd better stop arguing and do as you are told. cant help doing 禁不住 to do不能帮助干 They couldnt help jumping up at the news. Sorry I have lots of work to do.So I c
16、ant help to make up the room for you. go on to do 做不同的事或不同内容的事 doing 继续不停地做某事，指同一动作的继续 He went on to talk about world situation.他接着又谈了世界形势。 Well go on fighting so long as there is oppression inthe world. leave off to do 离开某地去干什么（目的状语） doing停下某事 Its time to leave off talking and to start acting. They
17、 left off to go fishing. 三、做表语 不定式作表语表示具体动作或将来动作；动名词作表语表示抽象的一般行为。 To be kind to the enemy is to be cruel to the people. My chief purpose is to point out the difficulties ofthe matter. What I would suggest is to put off the meeting. 当主语和表语都是不定式时，其含义一是条件，一是结果（例）。当主语是aim,duty,hope,idea,mista ke,plan,pu
18、rpose,suggestion等为中心词的名词词组（例）时，或以what引导的名词性分句（例），不定 式说明主语的内容。 Our work is serving the people. What he likes is taking a walk after supper. The story told by Mr.Wang is interesting. 句动名词作表语，与主语部分可以转换，如Serving thepeople is out work,而句中是现在分词作 表语，说明主语的性质、状态，现在分词具有形容词的各种特征，另外，动名词作表语还应与进行时态区别开 来。 四、作定语 不定
19、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： The next train to arrive is from Washington. Have you anything to be taken to your sister? Do you have anything to say on the question? Would you please give me some paper to write on? My 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）
20、。 (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）。 (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）；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）。 (4)不定式作定语时，一般可转换为定语从句，例to arrive=that will arrive。 动名词作定语 This passage can be used as listening materials. The reading room of our school library can hold 800people. All movin
21、g bodies have energy. 句动名词作定语说明一种性能，即：用来的；第句为现在分词作定语，单个分词作定语常置于 被修饰词之前，与被修饰词之间，可构成逻辑上的主谓关系，分词短语作定语常置于被修饰词之后。如：The man standing at the school gate is Professor Hua. 五、不定式作补足语 作宾语补足语 一些及物动词除要求按宾语外，有时还需要有宾语补足语，说明宾语的行为、状态、特征，这时意思才相 对完整。 (1)常要求不定式作宾补的动词有：allow,ask,advise,beg,cause,drive（强迫），encourage,exp
22、ect,forbid,force,get,would like (love,hate), order, permit, persuade, teach, tell, want, warn, wish等。如： Would you like me to give your regards to Mary? I want you to understand the whole passage clearly. (2)部分动词后常接to be形容词、名词短语等形式，有时to be可省略，如：believe,consider,discov er,find(=consider),feel (=think)
23、, imagine, judge, know, prove, think, suppose, see(=understand),understa nd等。 We all believe John(to be)honest. I consider him(to be)one of the best biology teachers of No. 1 Middle School. 但当不定式是完成式时，to不能省略，如：We consider him tohave been foolish. (3)感觉动词和使役动词后用作宾补的不定式须省略to。 I didnt hear anyone say a
24、nything about it. They make the students do too much homework every day. 这种句式在变为被动语态时，to不能省略，如第句：Thestudents are made to do too much homework every day. (4)help,know后面的to可有可无。如： Would you please help me(to) fill in the taxform? Ive never known her(to)be late before.但：He was known to have been to Fra
25、nce before. (5)部分短语动词后，常接不定式作宾补，如： You may depend on them to be there early. The Party calls on us to increase production and practise economy. 常这样用的短语动词有：ask for,care for,call on,count on,depend on,wait for,long for（渴望）， prepare for,wish for等。 作主语补足语 不定式作主语补足语，和主语构成一种逻辑上的主谓关系。如： He was not allowed
26、to enter the classroom for being late. The young university student is considered to have great promise. 六、不定式作状语 作目的状语 (1) I stayed there to see what would happen. Henry has decided to go to the hospital to be examinedby the doctor. (2)有时为了强调，不定式前可加in order或so as。如： Bob took down my telephone numbe
27、r so as(in order)not toforget it. 有时为强调目的状语可把in order to或不定式置于句首，但so as to不能这样用。在这种句式中不定式部 分可转换为so that,in order that,成为目的状语从句，如： I stayed there so that (in order that)I could see whatwould happen. (3)在部分表示感情色彩的形容词、过去分词或动词之后可接不定式，如：astonished,glad,happy,laugh ,pleased, sad,smile,sorry,surprised等。 We
28、 are glad to hear the news. I was surprised to see that a three-year-old baby could write so well. 在部分形容词后接不定式，用主动形式表示被动意义，这种句型中的主语是不定式的逻辑宾语。如：The question raised by thestudent is difficult to answer. The room is really comfortable to live in. 常这样用的形容词有：comfortable,easy,dangerous,difficult,expensive
29、,fit,impossible等。 作结果状语 We came home after our holiday to find our garden neat and tidy. 不定式作结果状语还常用在下列句式中。如： soas to;suchas to Im not so stupid(a fool) as to put it in writing.我不至于愚蠢到会把它写下来。 Im not such a stupid fool as to put it in writing. enoughto The speed is high enough for us to catch up with
30、 thefirst liner. only to Jane hurried back only to find her mother dying inthehospital. tooto Im too tired to stay up longer. 但在下列结构中，tooto并非是“太而不能”之意。如： Im only too glad to have passed the exam.考试及格我太高兴了。（too修饰glad to have，相当 于very） We have too much to learn.我们要学的太多了（不定式作定语）。 不定式短语还可作独立成分，用于句首、句中或句末。如： To tell the truth,the play was a great disappointment tome. 常见的短语有to be exact（确切地说），to begin with（首先），to do him justice（说句对他公道的 话），to be sure（真的）等等。 七、动词不定式、动名词的其它用法 疑问词不定式结构 疑问词who,what,which,when,where,whether,how后可接不定式构成不定式短语，在句中作主语、宾语、表 语等。如： When to leave for
