大學(xué)英語語法知識

1、大學(xué)英語語法知識動詞的時態(tài)動詞的現(xiàn)在時1. 一般現(xiàn)在時(1) 一般現(xiàn)在時表示經(jīng)常性的動作或狀態(tài)一般現(xiàn)在時表示經(jīng)常性動作或狀態(tài)時，常與often, always, usually, sometimes, every day等時間狀語連用。如：The shop opens at nine every day. 這家商店每天九點開門。It seldom snows here. 這兒很少下雪。(2) 一般現(xiàn)在時表示客觀存在或普遍真理Light travels faster than sound. 光速比聲速快。Food easily goes bad in hot weather. 天氣熱時食物容易壞

2、。(3) 一般現(xiàn)在時表示主語的特征或狀態(tài)The picture looks very beautiful. 這幅畫看起來很美。Air contains oxygen and nitrogen. 空氣含有氧和氮。(4) 一般現(xiàn)在時在時間和條件狀語從句中表示將來的動作或狀態(tài)I'll tell her about it as soon as I see her.When does the train arrive? 火車幾點到？(5) 用于圖片說明或劇本中的動作提示和背景說明INSIDE THE SHELTER: Stockton slowly turns to face his wife.

3、 The angry screaming cries of the people ring in their ears even as they depart. 防空洞中：斯道克頓慢慢轉(zhuǎn)過身，面對他的妻子。那群人正在離去，而他們憤怒的尖叫聲卻還回響在他們的耳邊。(6) 電視節(jié)目直播解說It's Carter to serve- he needs just one more point. He serves. And Smith misses. What a great serve!So the championshipgoes to 19-year-old Harry Carter.

4、該卡特發(fā)球了，他只需再得一分就贏了。他發(fā)球了，史密斯接球失誤。多漂亮的發(fā)球！冠軍屬于了19歲的哈利-卡特。2. 現(xiàn)在進行時(1) 現(xiàn)在進行時表示說話時或現(xiàn)階段正在進行的動作 表示現(xiàn)階段正在進行的動作，通常有表示現(xiàn)階段的時間狀語，如：today, this week, this month, this year, this term,now等。如： He is writing a novel now. 他目前正在寫一部小說。(2) 現(xiàn)在進行時表示經(jīng)常性的動作 現(xiàn)在進行時在表示經(jīng)常性、重復(fù)性或習(xí)慣性的動作時必須與only, merely, simply, really,fast, rapidly,

5、 steadily, forever, all the time, always, constantly, continually, repeatedly等頻度副詞連用。如： She is always complaining. 她總是在抱怨。(3) 現(xiàn)在進行時表示按計劃或已安排好要做的事 這一用法只適用于某些動詞，如：go, come, leave, start, arrive, return, spend, sail, meet, fly等。如： The guest is leaving by train tonight. 客人今晚坐火車走。(4) 補充說明1 在不少情況下，表示正在進行的

6、動作的漢語句子，并沒有“正在”這樣的字眼，但在譯為英語時必須用進行時態(tài)。如： It's raining heavily. 下大雨了。 How is everything going? 事情進展如何？2 有些動詞通常不能用進行時。不能用進行時的動詞有： 表示感覺或感情的詞，如：hear, see, smell, taste, feel, seem, notice, hate, love, like, want, wish, refuse, prefer, forgive等。 表示存在或所屬的詞，如：exist, stay, remain, obtain, have, own, form,

7、 contain等。 表示認識或理解的詞，如：understand, know, remember, forget, believe, think, doubt等。3. 現(xiàn)在完成時(1) 現(xiàn)在完成時表示從過去持續(xù)到現(xiàn)在的動作或狀態(tài)現(xiàn)在完成時的這種用法通常與由since或for引導(dǎo)的時間狀語連用。如：The old man have lived here for more than twenty years. 老人已在此住了20多年了。(2) 現(xiàn)在完成時表示過去發(fā)生的對現(xiàn)在有影響的動作1 現(xiàn)在完成時的這種用法有時不帶時間狀語，有時可以和already, before, ever, just, l

8、ately, never, once, recently, yet等一些所指時間不具體的時間狀語連用。如：Have you ever been to Australia? 你去過澳大利亞嗎？2 有時現(xiàn)在完成時和now, today, this morning, this week, this year等表示現(xiàn)在的時間狀語連用。如：I haven' t seen him today. 我今天沒見過他。I have seen him only once this year. 我今年只見過他一次。(3) 現(xiàn)在完成時在時間和條件狀語從句中表示將來完成的動作I'll go to the

9、party as soon as (or when) I have finished my homework.我完成作業(yè)后就去參加聚會。(4) 現(xiàn)在完成時和until now, so far, in the past few years, up to the present等表示從某時到目前這段時間的狀語連用 I have not heard from her so far. 到目前為止，我沒有收到過她的信。We have learned five hundred words up to the present.到目前為止，我們已學(xué)了五百個生詞。但要注意：當意義明確時，適用現(xiàn)在完成時的句子可以

10、不用時間狀語。如：He has done a lot of work. 他干了許多工作。She has told me about her story. 她跟我講過她的故事。4. 現(xiàn)在完成進行時(1) 現(xiàn)在完成進行時表示從過去一直持續(xù)到現(xiàn)在的動作或剛剛結(jié)束的動作I've been writing letters all this morning. 我寫了一上午信。（動作不再繼續(xù)）O'Neil is ill. He' s been lying in the bed for three weeks.奧尼爾在病中，已臥床3個星期了。（動作會繼續(xù)下去）(2) 現(xiàn)在完成進行時表示

11、從過去到現(xiàn)在的重復(fù)性動作現(xiàn)在完成進行時的這種用法所表示的并不是一直在進行的動作，而是斷斷續(xù)續(xù)地反復(fù)發(fā)生的動作。如：What have you been doing all this time? 你一直都在干什么來著？（動作可能繼續(xù)下去）That reporter has been contributing articles to this magazine all these years.這些年那個記者一直為這家雜志撰稿。（斷斷續(xù)續(xù)地反復(fù)發(fā)生的動作）動詞的過去時1. 一般過去時(1) 一般過去時表示過去的動作或狀態(tài)1 一般過去時通常與表示過去的時間狀語連用。與一般過去時連用的時間狀語有：yes

12、terday, last night(week, year, month, Sunday),then, at that time, at that moment, just now, a few days(weeks, months, years) ago等。例句：Lucy turned off all the lights before she went out. 出門前露茜關(guān)了所有的燈。2 一般過去時也可以與today, this week(month, year)等時間狀語連用，但這些時間狀語應(yīng)指過去。如：Did you see him today? 你今天見他了嗎？（today指今天已

13、過去的某一時刻）3 一般過去時還可以和for或since引導(dǎo)的時間狀語連用。如：I stayed there for two months. 我在那里呆了兩個月。Nothing happened since then. 打那以后什么事都沒有發(fā)生。(2) 有時一般過去時的時間狀語或是在上下文、或是暗含于句中Who was that? 那人是誰？I saw Ker in town. 我在城里看見了克爾。(3) 一般過去時在時間和條件狀語從句中表示過去將來的動作或狀態(tài)。Hans said he would let us know if he got any news. 漢斯說要是得到消息就告訴我們。

14、2. 過去進行時(1) 過去進行時表示過去某時正在進行的動作1 過去進行時通常和時間狀語連用。如：We were having dinner when they came.他們來的時候，我們正在吃飯。2 過去進行時表示過去某段時間內(nèi)持續(xù)的動作。如：Carlos was staying at home all last week.上周整整一周卡洛斯都在家呆著。They were building a dam last spring. 去年春天他們一直在修一個水壩。3 過去進行時表示與過去某個動作同時發(fā)生的動作。如：I was reading while she was writing. 我在讀書

15、，她在寫字。4 有時過去進行時用于主句，位于其后的when引導(dǎo)的從句表示意外發(fā)生的情況：I was walking in the street when it began to rain. 我正在街上走著，突然下起了雨。(2) 過去進行時表示過去將來的動作過去進行時的這種用法多表示過去的打算，通常僅限于come, go, leave, depart, start等一些表示移動的動詞。如：He didn't know whether she was coming. 他不知道她是否會來。The delegation was departing three days later. 代表團打算

16、三天后動身。3. 過去完成時(1) 過去完成時表示過去某時之前結(jié)束的動作或狀態(tài)When he got there, the train had already left.他到了那兒時火車已經(jīng)離開了。Ina realized she had made a mistake.艾娜意識到她犯了個錯誤。(2) 過去完成時與when等從句連用had+just / barely / hardly / scarcely+done.when., no sooner.than. 是表示“剛就”或“不等就”的固定句型。如：No sooner had we left the house than it began t

17、o rain. 我們剛離開家就開始下雨了。I had not gone much farther before I caught them up.我沒有走多遠就趕上他們了。(3) 過去完成時表示持續(xù)到過去某時之前的動作或狀態(tài)We had finished the work by nine o'clock yesterday.昨晚九點前我們已完成了工作。The company had completed the project by the end of 1999.到1999年底公司已完成了那個項目。(4) 過去完成時表示未實現(xiàn)的愿望過去完成時表示未實現(xiàn)的愿望的用法僅限于expect,

18、hope, intend, mean, plan, think,want等動詞，過去時間往往由一般過去時表達。如：I had intended to speak, but time did not permit. 我本想發(fā)言，可是時間不允許。I had hoped you might know. 我本希望你會知道的。4. 過去完成進行時過去完成時主要表示持續(xù)到過去某時之前的動作。如：I had been looking for it for days before I found it. 這個東西，我找了好多天才找著。The telephone had been ringing for thr

19、ee minutes before it was answered.電話鈴響了三分鐘才有人接。He was tired. He'd been working all day.他累了。他工作了一整天。After he'd been lecturing for half an hour, Professor Brown had a drink of water.布朗教授講了半小時課之后，他喝了一點水。動詞的將來時1. 一般將來時(1) 基本用法1 一般將來時常用來表示將來時間的動作或狀況。如：Helena will be twenty next year. 海倫娜明年就二十歲了。2

20、 一般將來時用于真實條件句和時間狀語從句的主句中表示將來的情況。如：I'll tell you as soon as he comes. 他一來我就告訴你。3 用于條件狀語從句表示愿望或意愿。如：If you will wait for me, I shall come back soon.如果你愿意等我，我馬上就回來。4 一般將來時可用來表示一種傾向或習(xí)慣性動作。如：The shop won't open until nine. 這家商店九點才會開門。Children will be children. 孩子就是孩子。(2) be going to 動詞原形這一結(jié)構(gòu)表示打算或

21、準備好要做的事或有跡象表明要發(fā)生的天氣變化等情況。如：What are you going to do during the summer holiday? 你暑假打算做什么？ The train is going to arrive. 火車就要到了。(3) 現(xiàn)在進行時（be 現(xiàn)在分詞）有些動詞的現(xiàn)在進行時可以表示將要發(fā)生的動作，表示按計劃或安排即將發(fā)生的事。這類動詞有：go, come, leave,start, arrive, return, spend, sail, meet, fly等。如：Annie is coming to supper this evening. 安妮今晚要來吃飯

22、。(4) be to 動詞原形這一結(jié)構(gòu)可表示約定、命令或按計劃要做的事。如：When are they to come? 他們什么時候來？We are to meet at the school gate. 我們約好在校門口見。 (5) be about to 動詞原形這一結(jié)構(gòu)表示“即將做”或“馬上做”的意思。如：He is about to leave. 他馬上就要動身。The vacation is about to start. 假期即將開始。2. 將來進行時將來進行時表示將來某一時間正在進行的動作。常表示已安排好之事，給人一種期待感。如：What will you be doing t

23、his time tomorrow? 明天這個時候你將做什么？The train will be leaving in a second. 火車馬上就開。3. 將來完成時(1) 將來完成時表示在將來某一時間之前完成的動作，往往對將來某一時間產(chǎn)生影響。如：I shall have finished reading the book by the end of this week.我將在本周末前讀完這本書。Before long,he will have forgotten all about the matter.過不久，他很快就會把這件事全然忘記。(2) 將來完成時表示持續(xù)到將來某時的動作或狀

24、態(tài)。如：By the time he graduates, he will have studied French for four years.到他畢業(yè)的時候，他學(xué)法語就滿四年了。By the time Pierce comes back from the meeting, we will have waited here for three hours. 到皮爾斯開會回來的時候，我們已經(jīng)在這兒等了三個鐘頭了。4. 過去將來時(1) 過去將來時表示過去某時之后將出現(xiàn)的情況，通常用于賓語從句中。如：I thought he would come. 我以為他會來。 Jenny never ima

25、gined that she would become a doctor.詹妮從沒想到自己會當醫(yī)生。(2) 表示從過去某時看將要發(fā)生的事情。如：The old lady was fifty-eight then. In two years she would be sixty.老太太當時五十八歲，再過兩年就六十了。I didnt think they would have any objection to it.我想他們不會有什么反對意見。(3) 表示過去習(xí)慣性動作（不管什么人稱都用would）。如：Whenever he had time, Harris would go to see hi

26、s grandmother. 哈里斯一有時間就去看他奶奶。Joanna would go for a walk after she had supper.喬安娜吃完晚飯總要去散步。被動語態(tài)現(xiàn)在范疇一般現(xiàn)在時am/is/are made現(xiàn)在進行時am / is /are being made 現(xiàn)在完成時has/have been made過去范疇 一般過去時was/were made過去進行時was/werebeingmade過去完成時had been made將來范疇一般將來時shall/will be made將來完成時shall/will have been made過去將來時should

27、/would be made過去將來完成時should/would have been made 1. 被動語態(tài)的各種時態(tài)被動語態(tài)（The Passive Voice）是動詞的一種形式，表示主語是謂語動詞的承受者。被動語態(tài)便于論述客觀事實，故常用于科技文章、新聞報道、書刊介紹以及景物描寫。被動語態(tài)沒有將來進行時、過去將來進行時和完成進行時形式。(1) 一般現(xiàn)在時的被動語態(tài)I am not so easily deceived. 我不會輕易上當受騙的。Computers are widely used in the world.計算機在世界范圍內(nèi)得到廣泛應(yīng)用。(2) 一般過去時的被動語態(tài)The

28、car was seriously damaged. 汽車受到嚴重損壞。Printing was introduced into Europe from China. 印刷術(shù)是由中國傳入歐洲的。(3) 現(xiàn)在進行時的被動語態(tài)The question is being discussed at the meeting. 這個問題現(xiàn)在正在會上討論。The children are being taken care of by their aunt. 孩子們現(xiàn)在正由其姑媽照看。(4) 過去進行時的被動語態(tài)When I called, tea was being served.當我來訪時，正值上茶之際。

29、When they arrived， the experiments were being made. 他們到達時，實驗正在進行。(5) 現(xiàn)在完成時的被動語態(tài)The meeting has been put off. 會議已被推遲了。The party has been planned since the new year. 這次聚會自新年起就已籌劃了。(6) 過去完成時的被動語態(tài)By the end of last month,he had been robbed at least three times.到上月底，他已被搶了至少三次。(7) 將來完成時的被動語態(tài)It is said tha

30、t the building will have been completed before September.據(jù)說大樓將于九月前竣工。This class will have been taught by Mr Brown for two years by next summer.到明年夏天，布朗先生在這兩個班執(zhí)教已有兩年了。2. 含有情態(tài)動詞的被動語態(tài)Water mustn't be wasted. 絕不能浪費水。Electric energy can be changed into light enery. 電能可以轉(zhuǎn)變成光能。Cross the road very caref

31、ully. Look both ways, or you might be knocked down.過馬路時要特別小心，要往兩邊看，不然會被撞倒。3. Get+過去分詞構(gòu)成的被動語態(tài)Get過去分詞也可以構(gòu)成被動語態(tài)，用這種結(jié)構(gòu)的句子側(cè)重于動作的結(jié)果而不是動作本身。如：the man got hurt on his way home. 那個男人在回家的路上受傷了。Mary is going to get married. 瑪麗準備結(jié)婚了。How did the glass get broken? 杯子怎么破了？4. 短語動詞的被動語態(tài)(1) 動詞+介詞This matter has been

32、talked about recently. 這件事近來一直被談?wù)撝uch a thing has never been heard of before.這樣的事從未被聽說過。The old man was looked after carefully. 那位老人被精心照顧著。He has never been listened to. 人家從不聽他的話。(2) 動詞+副詞The sports meeting was put off. 運動會被推遲了。A short play will be put on by them at the party. 一個短劇將要由他們在晚會上演出。What

33、 he said must be thought over. 他說的話必須仔細思考。(3) 其他短語動詞 Privileges must be done away with. 特權(quán)必須被取消。The light has just been turned off. 燈剛被關(guān)上。Their plans are being carried out. 他們的計劃正在執(zhí)行中。5. “主+動+賓+賓補”句型變?yōu)楸粍咏Y(jié)構(gòu)這種句型有兩個賓語，一般地說一為間接賓語，一為直接賓語。變?yōu)楸粍咏Y(jié)構(gòu)時，只將主動結(jié)構(gòu)中的一個賓語變?yōu)楸粍咏Y(jié)構(gòu)中的主語，另一賓語不變。We call him Xiao Wang. 我們叫他小王

34、。（主動句）He was called Xiao Wang. 他被叫做小王。（被動句）He painted the table green. 他把桌子漆成了綠色。（主動句）The table was painted green. 桌子被漆成了綠色。（被動句）6. “主+動+that從句”句型的被動句有些以that從句作賓語的主動句可以轉(zhuǎn)換成兩種形式的被動句。如：People say that he is the richest man in the city.人們說他是全市頭號富翁。It is said that he is the richest man in the city. 據(jù)說他是全

35、市頭號富翁。He is said to be the richest man in the city. 據(jù)說他是全市頭號富翁。當說話人認為主動句的主語無關(guān)緊要，或者不清楚誰是謂語動作的發(fā)出者時，便常常使用上述形式的被動句。如：It was reported that the boy had been found. 據(jù)報道，男孩已被找到。The boy was reported to have been found. 據(jù)報道，男孩已被找到。常用于上述被動句型的動詞有：acknowledge, assume, believe, claim, consider, declare, estimate,

36、 expect, find, know, presume, report, say, think等。 7. 含有被動意義的主動語態(tài)英語中有一些表示被動意義的主動句，其謂語所表示的不是主語的動作，而是其內(nèi)在的性能。這種句子的特點是：主語為無生命名詞，謂語動詞為一般現(xiàn)在時；肯定句必須帶方式狀語；否定句的謂語可以帶情態(tài)動詞。如：She is to blame. 她應(yīng)該受到責(zé)備。The house is to rent. 這個房子要出租。Food can keep fresh in a fridge. 食物放在冰箱里能保鮮。The pen writes smoothly. 這支鋼筆很好寫。The cl

37、oth feels soft. 這布摸上去很柔軟。The cake tastes good. 這蛋糕很好吃。助動詞be、have和do1. Be動詞的用法(1) 助動詞be和現(xiàn)在分詞一起構(gòu)成進行時或完成進行時。如：He is reading. 他在讀書。I'll be waiting for you there then. 我到時在那兒等你。(2) 助動詞be和過去分詞一起構(gòu)成被動語態(tài)。如：Is he taken good care of? 他被照顧得好嗎？They shall be punished. 他們一定要受懲罰的。(3) 助動詞be用作系動詞。如：Matthew is a t

38、eacher. 馬修是個老師。We were late today. 我們今天遲到了。(4) 助動詞be和不定式連用，可以表示下面幾種情況。表計劃，只用于肯定句和疑問句。如：We are to discuss it the following week. 我們打算下周討論那件事。When is the wedding to be? 婚禮什么時候舉行？表命令，只用于肯定句和否定句。如：All junior officers are to report to the colonel at once. 全體下級軍官都必須立即向上校報到。Tom says I am to leave you alone

39、. 湯姆要我不理會你。表可能，多用于被動結(jié)構(gòu)。如：Her father was often to be seen in the bar of this hotel.在這家旅館的酒吧經(jīng)常可見到她父親。Where is he to be found? 在哪兒可找到他？表示“必須”，“應(yīng)該”多用于現(xiàn)在式。如：Nobody is to leave this room. 誰也不許離開這個房間。What am I to do next？下一步我該做什么？He's to blame. 該怪他。表注定，多用于過去式。如：He was to be my teacher and friend for ma

40、ny years to come. 在后來許多年里，他是我的老師和朋友。The professor did not know at the time that he was never to see his native place again.當時教授不知道他再也見不到他的故土了。(5) 助動詞be用于條件從句。如：If we are to succeed, we must redouble our efforts.我們要想成功，必須加倍努力才行。（are to意為“想要”）(6) be后接going to, about to, on the point of等表示將來時間或根據(jù)計劃、意圖等

41、將要發(fā)生的事。如：It's going to rain. 快要下雨了。(將來時間)He's about to leave. 他正要走。(將來時間)2. Have的用法(1) 助動詞have與過去分詞一起構(gòu)成各種完成時態(tài)。如：I have read the book. 我讀過這本書。Kenny has left. 肯尼已經(jīng)走了。(2) 助動詞have與been+現(xiàn)在分詞構(gòu)成各種完成進行時態(tài)。如：I have been washing the clothes the whole morning.整個上午我都在洗衣服。Lambert has been working as a wor

42、ker here for nearly five years.蘭伯特一直在這里當工人，幾乎有五年了。(3) 助動詞have構(gòu)成had better, had best, had rather等詞組。Had better和had best是“最好還是”或“還是好”的意思。在had better中，had不表示過去時間，不能用have或has代替。had better 后可接不帶to的不定式或接進行式、完成式或被動語態(tài)。had better的否定式是had better not。如：You had better stay at home你最好呆在家里。You'd better have h

43、ad that experience before. 假如你以前有過那個經(jīng)驗就好了。You'd better not run the risk. 你最好不要冒那個險。(4) 補充Have還可用作使役動詞和實義動詞(表示”有”,”吃”等意義)。如:They have had the problem solved.他們讓其他人解決了這個問題.(使役動詞)Bad news has wings. 丑事傳千里. (實義動詞)What shall we have for lunch? 我們午飯吃甚么? (實義動詞)3. Do的用法(1) 助動詞do, does和did用于構(gòu)成否定句、疑問句和倒裝句

44、。如：Do you understand all this? 你明白這一切嗎？Don't go yet. 先別走。(2) 助動詞do, does和did用于代替句中的主要動詞，以避免重復(fù)。如：He didn't go to the party. Neither did I. 他沒有去參加晚會，我也沒有去。I do not agree. Nor does he. 我不同意，他也不同意。(3) 用于加強語氣， do， does和did位于陳述句的動詞原形前， do位于祈使句中的動詞原形前。如：Do have another cup of coffee before you go.走

45、前請一定再喝一杯咖啡。That's exactly what he did say. 他就是那樣說的。But I do want to go. 可是我確實想去。(4) 在一些以否定副詞如never, rarely, scarcely, only等為首的句子中，如果實義動詞是現(xiàn)在時或過去時，助動詞do和did可以構(gòu)成主謂倒裝。如：Never did I tell him about that. 我從來沒有告訴過他那件事。Rarely does it snow in the South. 南方很少下雪。情態(tài)動詞can、may、must的用法1. can的用法(1) can表示主語的能力。如

46、：The hall can seat 1,000 people. 這個大廳能坐1 000人。Can you play the piano? 你會彈鋼琴嗎？(2) can表示說話人的猜測（即可能性），多用于否定句和疑問句。如：Can it be true? 這能是真的嗎？The moon can't always be at the full. 月不可能總是圓的。What can she mean? 她可能是什么意思呢？(3) can表示許可。如：This sort of thing can't go on. 這樣的事不能再繼續(xù)下去了。You can't smoke he

47、re. 你不可在這里吸煙。(4)“can+完成式”表示說話人對過去情況的猜測（只用于否定和疑問結(jié)構(gòu)中）。如：He can't have missed the way.I explained the route carefully and drew him a map.他不會迷路。我對他詳細說明了路線，還畫了一張地圖。Can the team have left already? 球隊已經(jīng)離開了嗎？2. could的用法(1) could表示主語的能力，為can的過去時形式，如：Daisy couldn't come yesterday because she was ill.戴

48、西昨天不能來是因為她病了。They said they could swim. 他們說他們會游泳。(2) could表示說話人的猜測（即可能性）。如：He could be right. 他或許是對的。Could it be Henry? 可能是亨利嗎？At that time we thought the story could not be true.那時我們認為所說的事不可能是真的。(3) could表示許可。如：Father said I could swim in the river. 爸爸說我可以在河里游泳。Could I help you? 我能幫忙嗎？ (比Can I help

49、 you?婉轉(zhuǎn))The man asked if he could smoke in the hall.那個人問可不可以在大廳里吸煙。(4)“could+完成式”用于肯定句時一般表示過去可能完成卻未完成的動作。如：I could have reported you. 我本可以報告你的。You could have let me know earlier. 你本來該早一些告訴我。3. may的用法(1) may表示許可，多用于肯定句和疑問句中，否定句中不常用。如：May I ask you a question? 我可以問你個問題嗎？(比Can I ask you a question?更禮貌)

50、You may keep the book for two weeks. 這本書你可以借兩周。(2) may表示可能性，常用于肯定句和否定句中，指現(xiàn)在或?qū)淼目赡苄?。如：It may be true. 那可能是真的。The road may be blocked. 這條路可能不通了。(3)“may+完成式”表示說話人對過去情況的猜測。如：Eva may have missed her train. 伊娃可能誤火車了。He may have read the book. 他可能讀過這本書。(4) may as well(=might as well)是一個習(xí)語，作“不妨”或“完全有理由”或“還是

51、的好”解，用于提出建議。如：You may as well stay where you are. 你還是原地呆著好。All the pubs are closing.We may as well go home.所有的酒館都打烊了。我們還是回家吧。在對由may引出的“請求許可”的問句做出肯定回答時，通常不用過于嚴肅和正式的“Yes, you may.”，而多用“Yes, please?(請便)”或“Of course/ Certainly(當然可以).”；否定回答時，常用 “Please don't(請不要)”或“No, you mustn't(不行)”4. might的用法

52、(1) might表示許可。如：Might I have a word with you? 我可以同你說句話嗎？Might I make a suggestion? 我可以提一項建議嗎？Might we ask you a favour? 我們可以請你幫個忙嗎？但要注意：Might I.比May I.更客氣，但是不如May I.常用。(2) might表示說話人的猜測，其把握性比may小。如：Mr Smith might be right. 史密斯先生或許是對的。He might have some fever. 他可能有點發(fā)燒。(3) might用于委婉地提出建議、責(zé)備等。如：You mig

53、ht ask him for help. 你可以請他幫忙嘛。You might ask before you borrow my car. 你可以先問問我再借我的車嘛。(4)“might+完成式”（表示說話人對過去情況的抱怨、責(zé)備、遺憾等）。如：You might have considered her feelings. 你本應(yīng)考慮她的感受。You might have let me know earlier. 你本來該早一些告訴我。5. must的用法(1) must表義務(wù)或強制。如：I must go now. 我必須走了。Soldiers must obey orders. 軍人必須服

54、從命令。Visitors must leave bags in the cloakroom. 參觀者須把包放到物品寄存處。must用于一般疑問句時，其肯定答語應(yīng)用Yes, please.或I'm afraid so.其否定答語應(yīng)用needn't或don't have to.Must I go tomorrow? 明天我必須去嗎？Yes, please. 是的。No, you needn't. 不，你不必去。must的否定式must not/mustn't表示禁止。You mustn't leave here. 你不許離開這兒。Cars mustn

55、't be parked in front of the entrance. 車不能停在入口處。(2) must表示說話人有把握的猜測，僅限于肯定句。如：He must be at home now. 他現(xiàn)在肯定在家。You must be joking. 你一定是在開玩笑。He must be mad. 他一定是瘋了。(3)“must+進行式”表示對現(xiàn)在情況有把握的猜測，僅限于肯定句。如： You must be joking. 你一定是在開玩笑吧。(4)“must+完成式”表示對過去情況有把握的猜測，僅限于肯定句。如：You must have known what he want

56、ed. 你當時肯定知道他想干什么。Emm must have been very young when she got married. ?，斀Y(jié)婚時一定很年輕。(5)“must+完成進行式”表示對過去情況有把握的猜測，僅限于肯定句。如：He must have been working. 他肯定一直在工作。情態(tài)動詞的其他形式1. shall的用法(1) shall用于疑問句中，征求對方的意愿；這時可以用第一人稱和第三人稱。如：Shall I turn on the light? 要開燈嗎？(我把燈打開好嗎?)Shall we sit here? 咱們坐這兒怎么樣?(坐這兒好嗎?)Shall w

57、e begin now? 我們現(xiàn)在開始，好嗎？Shall he send you a check? 要不要他給你寄張支票？(2) shall用于陳述句，與第二人稱或第三人稱連用，表示允諾、命令、警告和強制，或表示說話人的決心等。如：She shall get her share. 她可以得到她的一份。(允諾)Then you shall come. 那你就得來.(命令) Nothing shall stop us from carrying out this plan.什么也不能阻止我們實現(xiàn)這項計劃。(決心)2. should的用法(1) should表“應(yīng)該”，用于所有人稱，表示常理認為是對的事或適宜做的事，通常意義為“應(yīng)該”。如：You should be more careful next time. 你下次應(yīng)該再細心些。We should always bear this in mi