大学英语语法(全).ppt

1、College English Grammar,大学英语语法,语法简介,语法的涵义、特点及分类 语法的三个层面：形式、意义、用法 掌握语法的重要性及语法教学的目标 英语语法的构成和特点 大学英语语法教学的重难点 如何更有效地掌握大学英语语法,语法是语言的规则 语法是词的构成、变化和用词造句的规则 语法包括词法和句法 语法是语言学的一个分支,研究按确定用法来运用的词类、词的屈折变化或表示相互关系的其他手段以及词在句中的功能和关系,语法的涵义,语法具有高度的抽象性 语法具有强大的递归性 语法具有严密的系统性 语法具有相对的稳固性 语法还具有民族性,语法的特点,从历时角度，可分为传统语法和现代语法

2、（以结构主义语言学出现为界） 从描写目的，可分为理论语法和教学语法 （英语语法属教学语法的范畴）,语法的分类,语法的三个层面:形式、意义、用法,形式：某个语法结构怎样构成的。比如“现在完成进行时”的结构形式是have been doing。这是使用语法规则的起点，即首先要做到能够准确地构造某个语法结构，这是语法结构的准确性问题。,意义：某个语法结构表达的意义。比如“现在完成进行时”可以表示“一个活动从过去一直延续到现在说话时刻”这样的含义，这就是现在完成时态这一结构所具备的语法意义。由此可以看出，特定意义一般是对应于特定的结构形式的，或者说，特定的结构形式能够表达特定的意义（Particula

3、r forms will express their particular meanings）。对于一个句子，它的含义不仅仅是来自于句中所使用的词汇的含义，而是还有来自于其中特定语法结构所含有的语法意义。,用法：关于何时/为什么使用某一语法结构的问题。这与在实际交流中的语境有关系，即什么样的语境中，采用何种语法结构来表达特定的意义才合适，这是有关语法结构的合适型问题。意义和用法是密切相关的，有时难以严格界定。,某一特定的语法结构的形式、意义和用法这三者之间是相互联系的，图示如下：,形式（Form） 语法结构怎样构成 （准确性）,意义（Meaning） 语法结构表达什么意义 （表意性）,用法（U

4、sage） 何时/为什么使用 （合适性）,语法形式、意义、用法三者之间的关系： 英语学习者要能够准确地、有意义地、恰当地去运用英语语言结构。 做到这一点，才能真正灵活使用语法规则，并进而在思维高度上来使用英语。比如：,I have been coming to Beijing for fourteen years. 翻译一：我来北京有14年了。 翻译二：在过去这14年中，我常常来北京。,翻译二正确。 Have been doing 在英文中表示的是一个重复的动作，具体来说：用短暂动词（如come）的完成进行时（如have been coming）来表示到目前为止的一段时间内重复发生的动作。,因

5、此，知道语法结构的正确构造形式只是第一步，还要清楚其表达的语法意义。但知其二并不能保证能够正确使用，还要知道其用法。其用法与语言环境密切相关。,句子与语境 在真实的语言交际过程中，任何一个句子都不能够孤立存在，都有一个赖以生存的环境。甚至有时候，语境决定了一个句子真正要表达的意思。 比如下面这个电影对白发生在一位父亲与自己女儿的男朋友之间：,Father: Do you drink? Young Man: No,thanks,Im cool. Father: Im asking If you drink. Do you think Id offer alcohol to teenage dri

6、vers taking my daughter out?,这位父亲问他女儿的男朋友（其正准备开车带他女儿出门）：Do you drink?他真正的意思是问这个年轻男子是否有饮酒的习惯，即在询问情况，而不是问他现在想不想喝酒，即不是在提议。,因此，从交际的角度去看待语法，在具体语境中考查语法规则的使用，通过语篇、语境驾驭语法来达到十分具体的交际目的。我们不仅知道“应该”怎么说（what learners should say）,更应该去了解为什么英语本族语者要“这样”说（what native speakers of English actually do say and why）。,“要掌握一

7、门语言，首先要掌握其语法。只有掌握了语法，最终才能掌握语言，才能得心应手地运用之。” The first and most important step in gaining over the language is gaining control over its grammar. It is the knowledge of grammar that yields access to the rich possibilities of the language and the means to use it. -不列颠英语用法大全,掌握语法的重要性,“语言的科学和艺术” -英国著名语言学H

8、.Sweet,两个目标、三个阶段： 高级阶段 过渡阶段 初级阶段 由此看出学习语法知识是第一步，通过不断的练习才能实现向语言能力的转换，最终达到言语交际的目的。,练,语法教学的目标,外语语法学习示意图： 高级阶段 过渡阶段 初级阶段 学习方式,语法知识与语言技能 语法知识如何转化为语言技能，要做到下面两点： 首先，要“多思考”（think much）,要认真领悟书中所讲到的语法规则。认真思考语法规则背后的合乎情理的思维规律，把“课本上的语法”（a textbook grammar）变为“头脑中的语法”（a mental grammar）即逐渐培养自己运用英语思维的能力。,其次，要“多练习”（p

9、ractice much），这里的练习，不仅是指为了应付考试而做的大量的阅读练习和单项选择题练习，而是包括听、说、读、写、译全方位的练习，尤其是口语和写作这种语言产出能力的练习。,英语语法包括词法和句法 词法:名词（noun）、动词(verb)、形容词(adjective)、冠词(article)、数词(numeral)、介词(preposition)、代词(pronoun)、连词(conjunction)、副词(adverb)等词类的用法 句法：一般规则的用法和特殊规则的用法,英语语法的构成,英语语法构成示意图,动态中把握英语语法,把握英语句子由易到难的五个层次的变化 学会从动态发展的角度去

10、理解和思考语法在句子中的体现,英语句子五个层次的变化,简单的简单句 复杂的简单句 非简单句 复杂结构充当句子成分 从句套从句的结构,简单的简单句 六个最基本句型,以及其中包含的六种句子成分(主谓宾系表补)。 SV(主谓) SVO(主谓宾) SVP(主系表) SVOOC(主谓宾宾补) SVIODO(主谓双宾语) There be + O (There be),复杂的简单句 在六大句型基础上加三大修饰成分(定语、状语、同位语)后句子变得更加复杂了,但仍属于简单句(即句号前只有一个主谓结构)。 如： I left the beautiful city Beijing yesterday. 主 谓 定

11、 宾 同位 状,非简单句 当一个句号前出现两个、甚至更多个主谓结构时,简单句就变成了并列句或复合句。 并列句（并列连词连接） 复合句（从句引导词引导）,复杂结构充当句子成分 简单句子中的成分一般由简单的词或词组充当,而随着句子变长变难,句中的一个成分可能就会由长而且复杂的结构充当,如从句、非谓语动词短语、动词短语、形容词短语、介词短语等等。 如： Feeling upset and not wanting to try, I left the city which I loved. （分词短语作状语、从句作定语）,从句套从句的结构 一个复杂的句子中,可以有两个以上的从句,这些从句相互之间可以是

12、平行关系,也可以是从属关系(即从句套从句),这种情况理解难度较大。,如： The American economic system is organized around a basically private-enterprise, market-oriented economy in which consumers largely determine what shall be produced by spending their money in the marketplace for those goods and services thatthey want most. (1994年

13、考研英语passage 1),下面通过英汉语法的对比来看英语语法的特点,英语语法的特点,英汉语法对比,一、 汉语中有很多无主语句子或省略主语的句子，在用英语表达时，须补出主语（祈使句的情形例外）。如：,1、暑假过得很开心 The summer vacation is happy. (F) We/They had a good time in the summer vacation. (T) (上面的这个汉语句子实际上没有主语，“暑假”在句中是状语。译成英语时须加主语We/They/He/I 等。),2、天气糟透了。整天刮大风下大雨的。 The weather was so bad. It bl

14、ew hard and rained heavily all the day. （翻译时必须补出主语It。）,3、考试没过别泄气。 Dont lose heart if you dont pass the exam. （翻译时在从句中要补充出主语you.）,二、汉语中有很多无生物名词作主语，但在英语中要改用生物即人作主语。如： 1、你的英语真棒。 Your English is excellent. (F) You are excellent in English. ( T ),2、史密斯先生双目失明。 Mr Smiths eyes are blind. (F) Mr Smith is bli

15、nd in both eyes. ( T ),三、汉语中的一些句子以生物即人作主语，但受表语形容词的制约，在英语中不可以人为主语。如：,1、你方便的话，请在六点钟来。 Please come at six if you are convenient. (F) Please come at six if it is convenient to you. (T),2、你很难说服他不去逛街。 You are difficult to persuade him out of going shopping. ( F ) It is difficult for you to persuade him ou

16、t of going shopping. ( T ) 但是我们可以说：English is difficult to learn for some people.,四、汉语中有大量的无谓语动词句子，但英语是一种以动词为中心的语言，每个句子几乎都少不了谓语动词（省略句除外）。如：,1、这本书值得一读。 The book worth reading. ( F ) The book is worth reading. (T ),2、我父母每天都很忙。 My parents very busy every day. ( F ) My parents are very busy every day. (

17、 T ),五、汉语中及物动词与不及物动词、状态动词与动作动词的差别不大，界限不明，但在英语 中却有严格区别和固定的用法模式。如： 1、他与她结婚了。 He married with her. (with 是多余的),2、凡是党和人民所要求的，我一定做到。 Ill do what the Party and the people require me. ( 译句中require 后须加 of。),3、我开始学英语到现在已有十年了。 I have begun to learn English for ten years. (F) It has been ten years since I bega

18、n to learn English. (T),4、这本杂志我可以借多久？ How long can I borrow this magazine? (F) How long can I keep this magazine? (T) (borrow 是一个表示瞬间短暂行为的动作动词，当然不能与how long 连用。),5、父亲直到半夜才睡觉。 Father went to bed until midnight. (F) Father didnt go to bed until midnight. Or: Father stayed up until midnight. (T),六、在汉语中

19、，词形没有变化；在英语中却有丰富的词形变化。如：,医生建议他每天喝两杯牛奶。 The doctor suggest that he drinks two glass of milk every day. (F) The doctor suggests that he (should) drink two glasses of milk every day. (T),英语中名、形、副、动、数词等均有词形变化，其中以动词的形式变化最多，看下例：,1、西瓜切成了八等份。 The watermelon divides into eight equal shares. (F) The watermelo

20、n is divided into eight equal shares. (T),2、从这一角度看，情况似乎没那么令人失望。 Looking at in this way, the situation doesnt seem so disappointing. (F) Looked at in this way, the situation doesnt seem so disappointing. (T),强化重点、突出难点：情态动词、虚拟语气、从句、强调、倒装、否定、省略、主谓一致、比较等是大学英语语法的重难点 从词法、句法层面上升到语篇层面：大学英语语法教学则更偏重句法的教学。句法教学

21、体现在理解语篇当中的长难句,而理解长难句最多运用到的语法知识就是从句、平行比较结构和非谓语动词短语三大语法规则,大学英语语法的重难点,如：The change met the technical requirements of the new age by engaging a large professional element (分词短语作介宾)and prevented the decline in efficiency (and连接平行结构)that so commonly spoiled the fortunes of family firms (that引导定语从句)in the

22、second and third generation after the energetic founders.(1996年考研英语阅读理解passage 3),英语语法学得好不好，主要不是看你读了多少语法书，记了多少条语法规则，而是要看你在实践中能否正确掌握所学的这些语法规则能听懂，说得好，写得好，理解得好，译得准确。 要掌握好一个语法项目，就得靠多听、多说、多写、多读、多译，也就是做反复的、大量的、多样化的练习。,如何掌握英语语法,目录,（一）语气（虚拟语气） （二）情态动词 （三）形容词、副词及比较级、最高级 （四）代词及其指代一致 （五）主谓一致 （六）倒装结构 （七）省略问题 （八

23、）否定句及其惯常用法 （九）独立主格结构 （十）名词性从句,第一讲,语气,mood,Please sit down! I am a teacher./I am not a teacher./Are you a teacher? If I were you, I would do better.,Mood,英语中有三种语气： 祈使语气（Imperative mood） 直陈语气（Indicative mood） 虚拟语气（Subjunctive mood）,Subjunctive mood,If he had driven (drive) more carefully, he would not

24、 have had (have) the car accident yesterday.,虚拟语气是一种表示假设、意愿、建议、请求、命令、猜测、可能或主观打算的一种语气。,近两年虚拟语气在英语四六级中的考查情况：体现在翻译题型中,【CET-4:2006.6】 The professor required that we hand in our research report (s) . (我们交研究报告)。 【CET-6:2007.6】 It is absolutely unfair that these children (should) be deprived of the right t

25、o receive education . (被剥夺了受教育的权利).,Its time something was done/some measures were taken (采取措施) about the traffic problem downtown.,【CET-4:2006.12】 The victim would have survived (本来会有机会活下来)if he had been taken to hospital in time. 【CET-6:2007.12】 But for mobile phone, our communication would not ha

26、ve been so efficient and convenient. (我们的通讯就不可能如此迅速和方便),【CET-6:2007 】 If you had followed my advice/ suggestion, you would not have been in trouble. (听从了我的忠告， 你就不会陷入麻烦).,虚拟语气的考点归纳如下： (should)+动词原形的情形 wish, if only, it is time的用法 if或but for等引导的条件句,Summary,1.1 虚拟语气的类别,从虚拟语气的形式和内容两方面着眼，可将其分为三大类： be型虚拟语

27、气 Were型虚拟语气 条件虚拟语气,1.2 be型虚拟语气,Be型虚拟语气指在任何情况下，不分时态、人称，句子谓语动词统统使用原形动词的虚拟形式，be型虚拟语气主要有两种用途,1）用于含有命令、建议、要求等意义的结构中 含有上述意义的动词后的宾语从句 含有上述意义的名词后的同位语从句或表语从句 含有上述意义的某些It is +过去分词+that 或it is +形容词+that 的结构中 在英国英语中，这一类的虚拟语气也可以用should+原形动词的形式,The teacher insisted that we be in his office at 5 oclock. 老师坚持让我们五点钟

28、到他的办公室去。 The general ordered that his troops retreat from the frontline. 将军命令部队从前线撤退。,All I request of you is that you be punctual. 我只要你准时到。 It is essential that the new technique be introduced. 引进新工艺很重要。 It is imperative that you present yourself at the meeting. 你务必亲自出席会议。,Instructions are issued t

29、hat the war prisoners be released. 释放所有战犯的命令已经下达。 It is the committees decision that the meeting be put off until next Friday. 委员会决定会议延至下星期五举行。,常与be型虚拟语气连用的 动词主要有：advise,agree,decide,demand,insist,move,order,prefer, propose, request,require,suggest等 名词主要有：decision,advice.demand,instruction,order,ins

30、istence, proposal, requirement,resolution,suggestion等 形容词主要有：advisable,desirable,appropriate,essential,fitting, important,imperative,impossible,necessary,obligatory,proper,vital,urgent等,用于表示祝愿、诅咒、假定、让步、担忧等含义的结构和一些固定用法中。 这些虚拟语气多由某些特定的连接词引导，它们多为古英语虚拟语气的残余，现仅限于正式场合使用，一般可为直陈语气所取代。,如： If that be the case

31、, we have to give up our original plan. 倘若情况果真如此，我们将不得不放弃原定计划。 Whatever be your reason, you have no right to be rude to your elders. 无论你有什么理由，你都无权对长辈们粗鲁无礼。,They evacuated the building lest the wall collapse. 他们撤出了大楼，以防墙壁倒塌。 Though he slay me, will I trust in him? 即使他要杀我，我也要信赖他吗？ Long live our mother

32、land！ 祖国万岁！,God save his soul. 上帝保佑他的灵魂得到安息。 Far be it from me to accept his advice blindly.我决不会盲目接受他的意见。 Home is home, be it ever so homely. 家纵简陋，总归是家。 We can always lend you a helping hand if need be. 倘有必要，我们随时可以援一引手。,1.3 were型虚拟语气,Were 型虚拟语气主要指be动词在某些表示与事实相反的语境里使用固定的were形式 其他动词在类似的语境里使用过去时或过去完成体形

33、式的虚拟语气。,Were型虚拟语气主要用于表示与事实相反的愿望、假设、印象、看法等意义的结构中 Wish一类动词后的宾语从句 If only, as if, would rather/sooner, it is time 等短语后边的句子，如与现在情况相反，虚拟语气用动词的过去时（be动词用were）, 与过去情况相反，则用过去完成体形式,We earnestly wish he were here with us sharing our happiness. 我真希望他此刻正与我们在一起分享我们的快乐。 I do wish the frightful calamity had not bef

34、allen us. 我真希望那场可怕的灾难没有降临到我们头上。,If only his advice had been acted upon. 当时要是采纳了他的意见该有多好。 How dare you come in as if you owned the place? 你怎么敢象是这地方的主人似的随意进来？ I would rather we had dinner now. 我倒愿意现在就吃饭。,I would sooner he stayed at home. 我倒宁愿他现在呆在家里。 It is high time you turned over a new leaf. 现在该是你改过

35、自新重新做人的时候了。,1.4 条件虚拟语气,从总体上说，条件虚拟语气基本上可理解为是在直陈语气的基础上将时间点朝过去的方向推移了一步。 条件虚拟语气中与各时间情况相反的虚拟动词形式如下表：,1. 4.1与各时间基准相反条件虚拟语气例示 注意虚拟句中隐含的真实情况和作者、说话人的情感、意愿意义，如： If his suggestions had been acted upon, circumstances would have been entirely different. 倘若早将他的建议付诸实施，情况早就完全不同了。,If it hadnt rained so heavily I wou

36、ld surely have come to your meeting on Friday afternoon. 倘若不是天下大雨，我肯定会来出席你们星期五下午召开的会议。 If he knew you are here, he would certainly come to see you . 如果他知道你在这里，他肯定会来看你。,If she dyed her hair a little darker, she would look much younger. 如果她把头发染一点，她看起来会显得年轻很多。 If the sun should rise in the west, I woul

37、d not change my mind. 就是太阳从西边出来，我也不会改变主意。,1. 4.2省略if的条件虚拟语气 条件虚拟语气的条件从句中如有助动词、动词be或动词have时，可以将if省略，将以上这些词与主语位置倒置，这些用法往往见于比较正式的语体中，如：,Were it not for the heavy fog, the plane would have taken off on schedule. 要不是因为浓雾弥漫，飞机就会按预定时间起飞。 Were he allowed to exercise a choice, which would he choose of the th

38、ree? 倘若让他们使选择权，三者之中他将挑选哪一个？,Should there be a misfortune, how could its loss be lightened? 如果发生不幸，怎样才能减轻损失？ Had I known of your difficulties I would have helped you . 要是我当时知道你的窘境，我就会帮你了。,1. 4.3 错综条件虚拟语气 有时条件从句对应的时间基准与结果主句对应的时间基准可能会出现错位，如从句表示与过去事实相反的意义，主句表示与现在情况相反等，这时应该针对情况对动词形式予以调整，如：,If it had not

39、been for the prolonged drought in May ,we should reap a bumper harvest this year. 要不是五月那场持续的干旱，我们今年可能夺得大丰收。（条件从句与过去事实相反，主句与将来可能情况相反）,Had he not turned a deaf ear to my warning, he would not be in such a difficult situation. 倘若他对我的告诫不置若罔闻的话，他就不会陷入目前的困境了。（条件从句与过去事实相反，主句与现在情况相反）,Had he enough courage h

40、e would certainly take your challenge. 假如他有足够的勇气，他肯定会勇敢地接受你的挑战。（条件从句与现在事实相反，主句与将来情况相反）,Had you worked a bit harder, you would not have to be so extremely worried about the coming examination now. 如果你过去学习用功一点，现在也不必象这样为即将来临的考试忧心如焚了。（条件从句与过去事实相反，结果主句与现在情况相反）,1. 4.4 含蓄条件虚拟语气 有时条件虚拟语气的条件不是由从句表达的，而是由介词词组或

41、上下文等表达的，这样的虚拟语气称为含蓄条件虚拟语气，如：,We could not have achieved such brilliant achievement in the war without the selfless support from the allied forces. 要不是盟军的无私援助，我们不可能取得如此辉煌的成绩。,The plan would have turned out to be quite effective under other circumstances. 换个环境，该计划完全可能非常有效。,He would have got much highe

42、r scores in the final examination, but he was so lazy. 他本来在期末考试中得分会高得多的，只是他太懒惰了。,It was snowing heavily or we could have got there on time. 那天正值天降大雪，不然我们本来可以按时到达的。 With more capital, I would have succeeded. 假如有更多的资本，我可能会取得成功。 The same thing, happening in a crowded place, would have brought a great d

43、isaster. 假如相同的事件发生在人群拥挤的地方，一定会引起一场大灾难。,But for the doctors skill, he would have died. 要不是医生医术高明，他早就死了。 Five minutes earlier, and we could have caught the last train. 如果早到五分钟，我们就可以赶上一班火车了。 To hear him speak English, youd take him for an American. 假如你听他说英语，你会以为他是美国人。,Exercise One,1. If the earth sudde

44、nly _ spinning, we would all fly off it.（1990 年6月四级题） A. stopped B. had stopped C. has stopped D. would stop,2. “How should the city be run?” “If I _ a mayor, I would make the streets cleaner and hire more policemen.”（托福题） A. would B. were C. would be D. should,3. If the whole operation _ beforehand

45、, a great deal of time and money would have been lost.（1999年6月四级题） A. was not planned B. has not been planned C. had not been planned D. were not planned,4. Jean doesnt want to work right away because she thinks that if she _ a job she probably wouldnt be able to see her friends very often.（1996年1月四

46、级题） A. has to get B. were to get C. had got D. could have got,5. If I hadnt stood under the ladder to catch you when you fell, you _ now.（1999年1月四级题） A. wouldnt be smiling B. couldnt have smiled C. wont smile D. didnt smile,6. I apologize if I _ you, but I assure you it was unintentional.（1998年考研题）

47、A. offend B. had offended C. should have offended D. might have offended,7. It is of the utmost importance that you _ here on time.（1995年6月六级题） A. be B. shall be C. are to be D. must be,8. It is recommended that the project _ until all the preparations have been made.(1995年6月四级题) A. is not started B

48、. will not be started C. not be started D. is not to be started,9. Who would you rather his daughter _ in the same office.（2002年6月四级题） A. going B. to go C. have gone D. went,10. Church as we use the word refers to all religious institutions,_ they Christina, Islamic, Buddhist, Jewish, and so on.（200

49、1考研题） A. be B. being C. were D. are,Translation,1.要是我哥哥在这儿，一切都没有问题了。 If my brother were here, everything would be all right. 2.昨晚如果有时间，我就回来看你的。 If I had had time last night,I would have come to see you.,3.You would be much better now if you had taken my advice. 假如你接受了我的意见，你现在就会好得多。 4. As Commander-i

50、n-Chief of the armed forces, I have directed that all measures be taken for our defense. 作为陆海空三军的总司令，我已下令采取一切防御措施。,Listening Practice,Enjoy the following english songs and practice the subjunctive mood. Because I love you Shoulda woulda coulda,Oral Practice,Suppose tomorrow was Teachers Day. You wan

51、ted very much to celebrate it for your middle school teacher，but you would be very busy then. What would you do then? Talk over your planning with your partners. Whenever you have difficulties with grammar，do consult with your partners.,Writing Practice,First, write a short Passage with the title “

52、If I were Bill Gates” in15 minutes. Then, exchange your work with your partner and point out the grammatical errors in the writing for each other. Finally, corret the errors in your own writing . Pay attention to the usage of the subjunctive mood in it.,第二讲,情态动词,modal verb,Olympics: He believes rowe

53、rs could have done better.,A gold and two bronze is an amazing achievement but I think all of us would agree that if everything went our way we could have gone better, he said.,情态动词的特征 情态动词（modal verb)表示说话人的语气或情态。情态动词本身虽有词义，但不完全，不能单独作谓语动词，只能和不带to的动词不定式连用，一起构成谓语动词。情态动词没有人称和数的变化。,2.1 情态动词的现在完成式的用法 情态动

54、词现在完成式主要有两个功能： 表已经发生的情况和表示虚拟语气。,在这两个方面must/mustnt; can/cant; need/neednt;may/maynt;might/mightnt; should/shouldnt；ought to等情态动词完成式表示的意思是有一定区别的,2.1.1表示已经发生的情况。 1）must have+过去分词，表示对已发生情况的肯定推测，译为“（昨天）一定”。,如： My pain_ apparent the moment I walked into the room, for the first man I met asked sympathetica

55、lly：“ Are you feeling all right?” A must be B had been C must have been D had to be,2）cant / couldnt have+过去分词，表示对已发生情况的否定推测，译为“（昨天）一定没”。,如： Mary _ my letter; otherwise she would have replied before now. A couldnt have received B ought to have received C has received D shouldnt have received,3）may /

56、 might have +过去分词，表示对已发生的事情做不肯定、可能性很小的推测，或事实上根本没发生，译为“也许”。,如: At Florida Powers Crystal River plant, a potentially serious leakage of radioactive water may have been unknowingly caused by an electrician.,2.1.2表示虚拟语气 1) neednt have + 过去分词，表示做了不必做的事，相当于”didnt need to do”,译为“其实没必要”。,如： You neednt have

57、come over yourself. As it turned out to be a small house party, we _ so formally. A neednt dress up B did not need have dressed up C did not need dress up D neednt have dressed up,2）should have +过去分词，表示应该做某事但实际上未做，译为“本应该”；should not + have过去分词表示本不应该做某事但实际上做了，译为“本不应该”。,如： I regret having left the wor

58、k unfinished; I should have planned everything ahead carefully. 我本来应该事先认真地把每件事情规划的很好，但实际上作者还是没有规划好，以至工作没有完成。,3) ought to have +过去分词，表示动作按理该发生了，但实际上未发生，译“该”，与should 的完成式含义类似。,如： The porter ought to have called the fire-brigade as soon as he saw the fire in the stock, which went up in smoke .,4) could

59、 have +过去分词，表示过去本来可以做但却未做，译为“完全可以”。这点与ought/should/ have +过去分词用法相似。,如： What you said is right, but you could have phrased it more tactfully.,5) may/ might have +过去分词，表示过去可以做但实际未做，译为“（那样）也许会”,如： It might have been better to include more punchy statistics and photos of equipment in the introduction to further assist first-time office aut