【文章內(nèi)容簡介】 uppose,see(=understand),understa nd等。 ①We all believe John(to be)honest. ②I consider him(to be)one of the best biology teachers of No. 1 Middle School. 但當不定式是完成式時，to不能省略，如：We consider him tohave been foolish. (3)感覺動詞和使役動詞后用作賓補的不定式須省略to。 ①I didn39。t hear anyone say anything about it. ②They make the students do too much homework every day. 這種句式在變?yōu)楸粍诱Z態(tài)時，to不能省略，如第②句：Thestudents are made to do too much homework every day. (4)help,know后面的to可有可無。如： Would you please help me(to) fill in the taxform? I39。ve never known her(to)be late before.但：He was known to have been to France before. (5)部分短語動詞后，常接不定式作賓補，如： You may depend on them to be there early. The Party calls on us to increase production and practise economy. 常這樣用的短語動詞有：ask for,care for,call on,count on,depend on,wait for,long for（渴望）， prepare for,wish for等。⒉作主語補足語 不定式作主語補足語，和主語構(gòu)成一種邏輯上的主謂關(guān)系。如： ①He was not allowed to enter the classroom for being late. ②The young university student is considered to have great promise. ⒊不定式短語還可作獨立成分，用于句首、句中或句末。如： To tell the truth,the play was a great disappointment tome. 常見的短語有to be exact（確切地說），to begin with（首先），to do him justice（說句對他公道的 話），to be sure（真的）等等。不定式作表語表示具體動作或?qū)韯幼?；①To be kind to the enemy is to be cruel to the people. ②My chief purpose is to point out the difficulties ofthe matter. ③What I would suggest is to put off the meeting. ⒉動名詞作主語 Learning without practice is no good. 動名詞作主語時，也常用It句式。如： ①It39。s +no good(no use,fun,a pleasure,a waste of time)+doing… It39。s no good reading in dim light. It39。s no use sitting here waiting. ②It39。s＋形容詞＋doing It39。s dangerous swimming in the sea in windy days. 這樣用的形容詞有expensive,nice,tiring等，但important,necessary則不適用于這種結(jié)構(gòu)，應(yīng)用不定式 代替，如：It39。simportant for you to keep fit. ③There is no+doing There is no saying what will happen next. 在這一結(jié)構(gòu)中，動名詞后常帶賓語，相當于It39。s impossible to…結(jié)構(gòu)。 ⒊動詞不定式和動名詞作主語的區(qū)別 ①不定式作主語經(jīng)常表示具體動作，常與特定的動作執(zhí)行者聯(lián)系在一起；而動名詞作主語經(jīng)常表示抽象動作，經(jīng)常不與特定的動作執(zhí)行者聯(lián)系在一起。如： It39。s no good eating too much fat. It39。s no good for you to eat so much fat. ②動名詞結(jié)構(gòu)作主語，可以用名詞或代詞屬格形式作邏輯主語。如： It39。s no use your pretending that you didn39。t know the rules.二、作賓語 ⒉動名詞作賓語 ①以下動詞后，只能接動名詞作賓語，如：admit,appreciate,consider,delay,enjoy,finish,keep,imag ine,mind,miss,practise,resist,risk,save,suggest,don39。t 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. ②動名詞作介詞的賓語 I should go to attend the birthday celebration instead of staying at home. What about inviting Li Jun to make a speech? 動名詞前的介詞有時可以省略，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。 ⒊部分動詞后面，既可接動詞不定式，也可接動名詞作賓語，意義不變。如：begin,continue,start,hat e,like,love,need,require,want等。 在need,require,want后接ing形式，表示被動意義，也可接不定式，但要用被動形式，如：Your handwr iting needs improving(tobe improved). hate,love,like接不定式表示特定的未來事件，接動名詞表示目前正在進行的活動或一般的行為。 在下列情況下，一般要用不定式： ①hate,like,love前有would(should)時，如：I39。d like to have a cup of coffee. ②當謂語動詞begin,continue,start等是進行式時，如：Thestudents are starting to work on the di fficult maths problem.③begin,continue,start與know,understand等狀態(tài)動詞連用時，如：I soon began to understand what was happening. ⒋advise,allow,encourage,forbid,permit等動詞后接動名詞作賓語，或帶不定式作賓語補足語。如： Our teachers don39。t permit our swimming in the lake. Our teachers don39。t permit us to swim in the lake. ⒌部分動詞后接不定式或動名詞時，意義差別較大，應(yīng)根據(jù)句子語境選擇使用。 ①forget,remember,regret后接不定式，表示現(xiàn)在或未來的動作，接動名詞表示動作已經(jīng)發(fā)生。如： Don39。t 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 tell you that all of you are not invited toattend the meeting. They regretted ordering these books from abroad. ②mean to do 打算做某事 doing 意味著…… I meant to catch up with the early bus. This means wasting a lot of money. ③try to do 設(shè)法盡力做某事 doing 試著做某事 You should try to overe your shortings. Try working out the physics problem in another way. ④stop to do 停下一件事去做另一件事（不定式作目的狀語） doing 停止做某事 On the way to the airport,I stopped to buy a paper. You39。d better stop arguing and do as you are told. ⑤can39。t help doing 禁不住…… to do不能幫助干…… They couldn39。t help jumping up at the news. Sorry I have lots of work to I can39。t help to make up the room for you. ⑥go on to do 做不同的事或不同內(nèi)容的事 doing 繼續(xù)不停地做某事，指同一動作的繼續(xù) He went on to talk about world 。 We39。ll go on fighting so long as there is oppression inthe world.⑦leave off to do 離開某地去干什么（目的狀語） doing停下某事 It39。s time to leave off talking and to start acting. They left off to go fishing. 三、做表語 動名詞作表語表示抽象的一般行為。當主語和表語都是不定式時，其含義一是條件，一是結(jié)果（例①）。當主語是aim,duty,hope,idea,mista ke,plan,purpose,suggestion等為中心詞的名詞詞組（例②）時，或以what引導的名詞性分句（例③），不定 式說明主語的內(nèi)容。 ④Our work is serving the people. ⑤What he likes is taking a walk after supper. ⑥The story told by is interesting. ④⑤句動名詞作表語，與主語部分可以轉(zhuǎn)換，如Serving thepeople is out work,而⑥句中是現(xiàn)在分詞作 表語，說明主語的性質(zhì)、狀態(tài)，現(xiàn)在分詞具有形容詞的各種特征，另外，動名詞作表語還應(yīng)與進行時態(tài)區(qū)別開 來。 四、作定語動名詞作定語 ①This passage can be used as listening materials. ②The reading room of our school library can hold 800people. ③All moving bodies have energy. ①②句動名詞作定語說明一種性能，即：用來……的；第③句為現(xiàn)在分詞作定語，單個分詞作定語常置于 被修飾詞之前，與被修飾詞之間，可構(gòu)成邏輯上的主謂關(guān)系，分詞短語作定語常置于被修飾詞之后。如：The man standing at the school gate is Professor Hua. 動詞不定式、動名詞的其它用法 ⒈疑問詞＋不定式結(jié)構(gòu) 疑問詞who,what,which,when,where,whether,how后可接不定式構(gòu)成不定式短語，在句中作主語、賓語、表 語等。如： ①When to leave for London has not been decided yet. ②Mr. Smith didn39。t know whether to leave or stay there. ③I asked Professor Xu how to learn English well. ④The question was where to get the medicine needed. 以上例句中疑問詞＋不定式部分，均可轉(zhuǎn)換為相應(yīng)的從句形式。如：①When we shall leave… ③…h(huán)ow I could learn… 經(jīng)常在這種結(jié)構(gòu)中使用的動詞有：consider,decide,discover,explain,find out,forget,hear,know,lea rn,observe,understand,wonder等。 ⒉動詞不定式的時態(tài)、語態(tài) (1)時態(tài) ①一般式：動詞不定式一般式表示的動作發(fā)生在謂語動詞之后，有時表示同時發(fā)生。如： I hope to bee a university