倒装、强调、否定、省略

nullnull倒装 强调 省略 反义疑问句 null完全倒装的四种主要类型 部分倒装用法归纳 练习完全倒装的四种主要类型完全倒装的四种主要类型1. here 和there位于句首时的倒装 表示地点的here和 there位于句首时，其后用完全倒装形式。这类倒装句的谓语通常是动词be和come, go等表示移动或动态的不及物动词： Here’s Tom. 汤姆在这里。 There’s Jim. 吉姆在那儿。 Here comes the bus. 公共汽车来了。 There goes the bell. 铃响了。 There goes the last train. 最后一班火车开走了。null【注意】 (1) 以上倒装句中的谓语动词come和go不能用进行时态，即不能说 Here is coming the bus。 (2) 若主语为代词，则不倒装： Here I am. 我在这儿。/ 我来了。 Here it comes. 它来了。 (3) 其中的动词有时也可能是stand, lie, live等表示状态的动词(表示存在)： There stood a desk against the wall. 靠墙放着一张书桌。 Once upon a time there lived a man known by the name of Beef. 从前有个人名叫比夫。null2. away和down等位于句首时的倒装 地点副词away, down, in, off, out, over, round, up 等位于句首时，其后用完全倒装语序。这类倒装句的谓语通常表示动态的不及物动词： Away went the runners. 赛跑选手们跑远了。 Round and round flew the plane. 飞机盘旋着。 The door opened and in came Mr Smith. 门开了，史密斯先生进了来。 Down came the rain and up went the umbrellas. 下雨了，伞都撑起来了。null【注意】 若主语为人称代词，则不能用倒装： Away he went. 他跑远了。 Down it came. 它掉了下来。null3. 状语或表语位于句首时的倒装 为了保持句子平衡或使上下文衔接紧密，有时可将状语或表语置于句首，句中主语和谓语完全倒装： Among these people was his friend Jim. 他的朋友吉姆就在这些人当中。 By the window sat a young man with a magazine in his hand. 窗户边坐着一个年轻人，手里拿着一本杂志。null【注意】 在表语置于句首的这类倒装结构中，要注意其中的谓语应与其后的主语保持一致，而不是与位于句首的表语保持一致。比较： In the box was a cat. 箱子里是一只猫。 In the box were some cats. 箱子里是一些猫。null4. 分词和不定式置于句首的倒装 有时为了强调，可将谓语部分的现在分词、过去分词或不定式置于句首，从而构成倒装： Buried in the sands was an ancient village. 一个古老的村庄被埋在这沙土之中。 Standing beside the table was his wife. 站在桌旁的是他的妻子。 To be carefully considered are the following questions. 下列问题要仔细考虑。部分倒装用法归纳部分倒装用法归纳1. 否定副词位于句首时的倒装 在正式文体中，never, seldom, rarely, little, hardly, scarcely, no sooner, no longer, nowhere 等含有否定意义的副词若位于句首，则其后要用部分倒装： I shall never forgive him. / Never shall I forgive him. 我永远不会宽恕他。 He seldom goes out for dinner. / Seldom does he go out for dinner. 他很少出去吃饭。null She hardly has time to listen to music. / Hardly does she have time to listen to music. 她几乎没时间听音乐。 He little realizes how important this meeting is. / Little does he realize how important this meeting is. 他不甚明白这个会议的重要性。 We had no sooner reached the airport than the plane took off. / No sooner had we reached the airport than the plane took off. 我们刚到机场,飞机就起飞了。null【注意】 (1) 对于not…until句型，当not until…位于句首时，其后的主句要用倒装语序： He didn’t leave the room until the rain stopped. / Not until the rain stopped did he leave the room. 雨停了之后他才离开这房间。 (2) 某些起副词作用的介词短语，由于含有否定词，若位于句首，其后要用部分倒装： On no accounts must this switch be touched. 这个开关是绝不能触摸的。 In [Under] no circumstances will I lend money to him.无论如何我也不会再借钱给他了。 但是，in no time(立即，马上)位于句首时，其后无需用倒装语序： In no time he worked out the problem. 他马上就算出了那道题。 null2.“only+状语”位于句首时的倒装 当一个状语受副词only的修饰且置于句首时，其后用部分倒装语序： Only then did he realize that he was wrong. 到那时他才意识到他错了。 Only in this way are you able to do it well. 你只有用这种方法才能把它做好。 Only when he returned home did he realize what had happened. 当他回到家里时，才知道出了什么事。null3. “so+adj. / adv.”位于句首时的倒装 副词so后接形容词或副词位于句首时，其后用部分倒装： So cold was the weather that we had to stay at home. 天气太冷，我们只好呆在家里。 So fast does light travel that we can hardly imagine its speed. 光速很快，我们几乎没法想像它的速度。 So sudden was the attack that we had no time to escape. 袭击来得非常突然，我们来不及逃跑。null4.“so+助动词+主语”倒装 当要表示前面提出的某一肯定的情况也同样适合于后者，通常就要用“So+助动词+主语”这种倒装结构： You are young and so am I. 你年轻，我也年轻。 She likes music and so do I. 她喜欢音乐，我也喜欢。 If he can do it, so can I. 要是他能做此事，我也能。null【注意】 (1) 若前面提出某一否定的情况，要表示后者也属于同样的否定情况，则应将其中的so改为neither或nor： You aren’t young and neither am I. 你不年轻，我也不年轻。 She hasn’t read it and nor have I. 她没有读它，我也没有读。 (2) 注意该结构与表示强调或同意的“so+主语+特殊动词”结构的区别： "It was cold yesterday." "So it was." “昨天很冷。”“的确很冷。” "Father, you promised." "Well, so I did." “爸爸，你答应过的。”“嗯，是答应过。”null5. 由not only…but also引出的倒装 当not only…but also位于句首引出句子时，not only 后的句子通常用部分倒装形式： Not only is he a teacher, but he is also a poet. 他不仅是一位教师，而且是一位诗人。 Not only did he speak more correctly, but he spoke more easily. 不仅他讲得更正确，也讲得更不费劲了。 null6. 虚拟条件句的省略与倒装 当if引导的虚拟条件从句中含有had, were, should等时，如将if省略，则要将had, were, should等移到主语前，构成倒装句： Had you come yesterday, you would have seen him.若你昨天来，你就会见到他了。 Should you require anything give me a ring. 如果需要什么，可以给我打电话。 Were it not for your help, I would still be homeless. 要不是你帮助，我会仍然无家可归。 【注意】省略if后提前的had不一定是助动词： Had I money, I would buy it. 假若我有钱，我就会买它。倒装结构专练倒装结构专练1. No sooner ________ themselves in their seats in the theatre ________ the curtain went up. A. they have settled; before B. had they settled; than C. have they settled; when D. they had settled; than 2. I wonder if your girl friend will go to the ball. If she ________ , so ________ mine. A. does; does B. does; will C. will; does D. would; willnull3. It’s necessary that not only ________ to see a doctor but also stay at home for a good sleep. A. Bob should go B. did Bob go C. Bob’s going D. should Bob go 4. In ________ , but out ________ again. A. came the teacher; he went B. came the teacher; went he C. did the teacher come; he went D. the teacher came; went henull5. It’s beyond description. Nowhere else in the world ________ such a quiet, beautiful place. A. can there be B. you can find C. there can be D. can find you 6. Not until Dec. 2003 ________ caught by the US soldiers, and it was a great victory for the USA. A. was Saddam Hussein B. Saddam Hussein was C. had Saddam Hussein been D. Saddam Hussein had beennull7. Only after ________ his homework ________ to watch TV. A. he has finished; is he allowed B. has he finished; is he allowed C. he has finished; he is allowed D. has he finished; he is allowed 8. Form then on we never saw her again, nor ________ from her. A. heard we B. had we heard C. we have heard D. did we hearanull9. ________ our bus; we’ll have to wait for the next. A. Does there go B. It goes C. There goes D. Does it go 10. －It was careless of you to have left your new bike outside all night. －My god! ________ . A. So did I B. So I did C. So was I D. So were you null11. What a naughty boy he was! ________ . A. Down jumped he from the desk B. From the desk jumped he down C. He down jumped from the desk D. Down he jumped from the desk 12. On the opposite wall ________ one map ________ dozens of pictures. A. hang; including B. are hung; together with C. is hanged; with D. is hanging; as well as null13. You can never use my computer. At no time ________ that machine. A. you should touch B. should you touch C. touch should you D. you touch 14. Not until all the fish died in the river ________ how serious the pollution was. A. did the villagers realize B. the villagers realized C. the villagers did realize D. didn’t the villagers realize 强调句型强调句型 我们在说话、写文章的过程中，为了要突出句子中的某一部分时，就常使用某种方法、手段使它突出，以便能引起他人的注意，这就是强调。 英语中，表示强调的方法一般分为三种：位置的强调；用词强调；句型强调。null一、位置强调 英语句子的语序，一般为：主、谓、宾、表、状。有时为了强调某个成份，就故意将它移到句首或句末。如： A. 强调主语及状语。如： (1) I was reading English this morning. — This morning, I was reading English. 今天早晨，我一直在读英语。 (2) I’ll go to see Li Lei tomorrow. — Tomorrow, I’ll go to see Li Lei. 明天，我要去看李蕾。nullB. 强调谓语(as, though引导的让步状语从句) (1) Though he will try, he can’t succeed. — Try as / though he will, he can’t succeed. 尽管他会尝试，但他不会成功。 (2) Though she can sing, she can’t sing well. — Sing though / as she can, she can’t sing well. 尽管她会唱，但唱得不好。nullC. 强调宾语或表语(as, though引导的让步状语从句) (1) Though he learnt English, he didn’t learn it well. — English as / though he learnt, he didn’t learn it well. 尽管他学过英语，但他学得并不好。 (2) Though he is ill, he keeps on working. —Ill as / though he is, he keeps on working. 尽管他有病，他仍坚持工作。null二、用词强调 英语中强调的另一种方法，就是用不同的词进行夸张从而达到强调的目的。用词强调主要有以下几种形式。 A. 在句子中的谓语动词前加助动词do, 对谓语进行强调。如： (1) I do like swimming. 我的确喜欢游泳。 (2) He did go there last night. 他昨天晚上的确去过那儿。nullB. 用awfully, badly, dead, deeply, ever, extremely, highly, indeed, lightly, not…at all, particularly, pretty, really, so, strongly, terribly, utterly, very, very much,等副词修饰以加强语气。如： (1) He wants to get it very much. 他非常像得到它。 (2) I miss you terribly. 我非常思念你。nullC. 用短语at all, on earth, in the world, under the sun等表示强调，意思是：到底，究竟，根本。如： (1) I don’t know it at all. 我一点也不知道。 (2) What on earth are you doing there? 你到底在那干什么？nullD. 用重复某一个词或短语来强调。如： (1) He thought and thought, and suddenly he got a good idea. 他想啊想啊，突然想到了一个好主意。 (2) He ran and ran, and at last he caught up with other students. 他跑啊跑啊，终于赶上了其他的同学们。null三、用句子来强调 A．句型强调 英语中最常见的强调手段，也是我们必须要掌握的方法就是句型强调，即：强调句型。It is / was + 被强调的部分 + that (who)…如： (1) It was in the room that Li Lei was born. 李蕾出生就在这间房子。 (2) It is Wei Fang who has broken the record. 就是魏方打破了纪录。nullB．在使用强调句型时须注意的几个问题： (A) 原句子是现在时或将来时，强调句用It is + 被强调的部分 + that (who)…; 若原句子是过去时，强调句用：It was + 被强调的部分 + that (who)… (1) Li Lei’s father will work in America. —It is in America that Li Lei’s father will work. 李蕾的父亲的工作将就在美国。 (2) I studied at this school a few years ago. —It was at this school that I studied a few years ago. 几年前我就在这所学校读书。null(B) 即使被强调的部分是复数，It后面始终用单数形式。如 (1) Tom and Lucy gave us much help. —It was Tom and Lucy that gave us much help. 正是汤姆和露西给了我们很多的帮助。 (2) I saw swans in the lake yesterday. —It was swans that I saw in the lake yesterday. 昨天我看到在湖里的就是天鹅。null(C) 强调人时，可用who 代替that, 但若强调时间、地点、原因、方式时，不能用when, where, why, how代替 that。如： (1) It is our teacher who / that helps us make great progress. 正是我们的老师帮助我们取得了很大的进步。 (2) It is by bus that I go to school every day. 每天我就是乘公共汽车上学。null(D) 在强调not…until结构中的时间状语时，应将not移到until前，再将not until部分移到被强调的位置。如： I didn’t go to bed until twelve o’clock last night. — It was not until twelve o’clock last night that I went to bed. 昨天晚上我一直到十二点才睡。null(E) 强调一般疑问句中的某一成分时，将强调句中的主句用一般疑问语序。如： (1) Do you like English?—It is English that you like? 英语就是你喜欢的吗？ (2) Will you go to London?—It is London that you will go to? 你要去的就是伦敦吗？ (F)特殊疑问句中只有疑问词可以被强调。句型为：特殊疑问词+be + it that+…? 如： (1) What made him so angry?—What is it that made him so angry? 是什么东西使他如此生气？ (2) Why did she cry?—Why was it that she cried? 是什么原因使他哭了起来？null(G) 强调主语时，who 或that后面的谓语形式须与被强调的主语保持一致。如： (1) Lily speaks Chinese very well. —It is Lily who / that speaks Chinese very well. 李丽的汉语讲得很好。 (2) Children like stories. —It is Children that like stories. 孩子们喜欢故事。 (H) 强调句中的be前可用表推测的情态动词：must, can, may等。如： (1) It must be Piney that sent us this present. 肯定是Piney 给我们寄来了这件礼物。 (2) How can it be that he didn’t pass the exams. 他考试没有通过怎么可能呢？null(I) 强调句型不用于强调谓语、表语、since, as等引导的原因状语从句。如： He is better today since he can walk around without my help. 就不能有下列强调形式： It is better today that he is today since he can walk around without my help. (错) It is since he can walk around without my help that he is better today. (错) null易错题分析 1. _____ was very ______ that little Jim wrote the letter. A. It, careful B. It, carefully C. He, careful D. He, carefully 2. It was when she was about to go to bed ______ the telephone rang. A. since B. as C. that D. then null3. It may have been at Christmas _____ John gave Mary a handbag. A. before B. who C. that D. when 4. ________ that caused him to serve dinner an hour later than usual. A. It was we being late B. It was our being late C. It was we were too late D. It was because we were late null5. “Where did you find the professor who made the speech yesterday?” “It was in the hall ______ the students often have a meeting.” A. where B. which C. that D. when 6. It was what he meant rather than what he said ______ annoyed me. A. which B. as C. what D. thatnull7. It was his nervousness in the interview ______ probably lost him the job. A. which B. since C. that D. what 8. It is the ability to do the job ______ matters not where you come from or what you are. A. one B. that C. what D. itnull9. Was it five o’clock ______the fire broke out? A. when B. that C. which D. in which 10. It’s more than half a century _____ my grandfather joined the Party and became a servant to the people. A. when B. that C. since D. while省略省略 省略是为了避免重复、突出新信息而省略句中的一个或者几个句子成分并使上下文紧密连接的一种语法修辞手段。在语言应用中，尤其在对话中，是一种十分普遍的现象。在英语考试中，也经常会采用微型语境的方法，使用省略手段来设计考试陷阱，增加考试的难度。在考试陷阱中，所涉及的省略情况一般有：词的省略、句子成分的省略、多个成分的同时省略等。null一、承前省略陷阱 所谓承前省略指的是当前后两句结构相同时，通常可将后一结构与前一结构相同的部分省略，从而使句子更简洁。一般说来，这种省略考生是可以根据上下文的语境作出正确理解的，但是，当这种省略与其他英语句型相似并很容易发生混淆时，就可能让张冠李戴，步入误区。如果命题者刚好抓住这一点来巧妙设题，就很可能构成有一定难度的陷阱题。如： 1.—What should I do with this passage? — _________ the main idea of each paragraph. A. Finding out B. Found out C. Find out D. To find outnull2. My friend Mary is _________ beautiful girl and _________ girl everyone likes to work with. A. a, a B. a, the C. the, a D. the, the 3. “What made her struggle to become an artist so hard?” “_________ she was a woman.” A. / B. When C. That D. Whatnull4. If the weather is fine, we’ll go. If _________, _________. A. not, not B. no, no C. not, no D. no, not 5. It is really _________ useful dictionary and _________ dictionary every one of us needs. A. a, a B. a, the C. the, a D. the, thenull二、语境省略陷阱 这里所说的语境省略指的是在一定的语境中，为了表达的简洁可省略有些不言而喻的信息。有时命题者巧妙地运用这一省略手段可编制出一些非常高明的语境省略陷阱题。如： 1. Boris has brains. In fact, I doubt whether anyone in the class has _________IQ. A. a high B. a higher C. the higher D. the highestnull2. How beautifully she sings! I have never heard _________ voice. A. a better B. a best C. the better D. the best 3. She’s too thin. She _________ gain some weight but she _________ too little. A. would, ate B. will, eats C. would, eats D. will, atenull三、结构省略陷阱 1. —Who has eaten all the cake, Jim? — Oh, _________ must your two pet dogs. A. it B. they  C. that D. which 2. If you are planning to spend your money having fun this week, better _________ it—you’ve got some big bills coming. A. forget B. forgot C. forgetting D. to forgetnull3. Why _________ skating there with us this afternoon? A. don’t go B. not to go C. not go D. go notnull四、状语从句省略陷阱 为了简洁起见，有的状语从句(如时间状语从句、条件状语从句、方式状语从句等)有时可省略从句的主语和部分谓语(尤其是当从句主语与主句主语一致，且从句谓语包括有动词be时)： While (he was) waiting, he saw Jim pass by. 他在等时见到吉姆路过。 He opened his mouth as if (he was) to speak. 他张开口好像要说话似的。 Often she would weep when (she was) alone. 她一个人时，常常哭泣。 I’d like to see you whenever (it’s) convenient. 你方便时我想来看看你。null 有些由if构成的省略结构，已属固定短语，如if any, if necessary, if possible, if not, if so。如： There are few, if any, mistakes in that book. 那本书就是有错误也不多。 If necessary, ring me at home. 如果必要，可以打电话到我家找我。 If possible, I wish to come next time. 如果可能，我希望下次能来。 He may be busy. If so, I’ll call later. If not, can I see him now? 他可能很忙，要是这样，我以后再来拜访。要是不忙，我现在可以见他吗?null1. He is a man of few words, and seldom speaks until _________ to. A. spoken B. speaking C. speak D. be spoken 2. If carefully _________, the experiment will be successful. A. do B. does  C. done D. doingnull3. The research is so designed that once _________ nothing can be done to change it. A. begins B. having begun C. beginning D. begunnull五、虚拟语气省略陷阱 在虚拟条件句中，有时可将引导条件从句的连词if省略，而将从句中的were, should, had 等提到句首。如： Were I Tom, I would refuse. 如果我是汤姆，我会拒绝。 I will go, should it be necessary. 假若有必要，我会去的。 Had it not been for the bad weather we would have arrived in time. 若不是天气坏，我们就准时到达了。null 值得注意的是，若条件从句为否定句，否定词not应置于主语之后，而不能与were, should, had 等缩略成Weren’t, Shouldn’t, Hadn’t而置于句首。另外，有时省略if后提前的had不是助动词。如： Had I time, I would come. 假若我有时间，我会来的。（=If I had time…） 1. It _________ very silly to argue any more against each other about it _________ true. A. will be; could that be B. must be; could that be C. should be; was that to be D. would be; should that benull六、让步从句省略陷阱 在由though, as引导的让步状语从句中，如果从句的表语是可数名词单数，将名词提前时，名词前面的冠词a 须省略。如： Child as [though] he is, he knows much about the society. = Though he is a child, he knows much about the society. 尽管他还是个小孩，他对社会的了解不少。null1. _________ as it is, it can understand you. A. A dog B. Dog C. Dogs D. The dog 2. _________, he talks a lot about his favorite singers after class. A. A quiet student as he may be B. Quiet student as he may be C. Be a quiet student as he may  D. Quiet as he may be a student反义疑问句的三种基本结构反义疑问句的三种基本结构结构一：肯定的陈述句 + 否定的简短问句？ It’s Monday today, isn’t it? 今天星期一，是吗？ He often goes to school by bike, doesn’t he? 他常常骑自行车上学，对吗？ They went to the park yesterday, didn’t they? 他们昨天去的公园，是吗？null 用法说明：前面陈述部分是肯定形式，后面简短问句用否定形式。简短问句的主谓部分通常由陈述部分的主谓语来决定，即人称一致，时态一致。 对于反意疑问句的回答，总的一个原则是：不管问题的提法如何，只要事实上是肯定的，就用 yes 回答，事实上是否定的，就用 no回答。但当陈述部分是否定句时，回答译成汉语时不一样。这与汉语截然不同，应特别注意。如： —You don’t want to go out, do you? 你不想出去，对吧？ —Yes, I do. / No, I don’t. 不，我想出去。/ 对，我不想出去。null结构二：否定的陈述句 + 肯定定的简短问句？ That isn’t your book, is it? 那不是你的书，是吗？ Jim doesn’t speak French, does he? 吉姆不会说法语，对吗？null用法说明：当陈述部分有 hardly, seldom, few, little, no, never, nothing, nobody, nowhere 等否定词时，疑问部分要用肯定形式。如： He never said she would come, did he? 他从来没说她会来，是吗？ Nobody can answer the question, can they? 没有人能回答这个问题，是吗？ Few people know about it, do they? 几乎没有人知道有关这件事情，是吗？ You have never seen the film, have you? 你从来没看过这部电影，是吗？ Neither you nor I can work it out, can we? 你我都不能算出它，对吗？ null结构三：祈使句 + 简短问句？ Stop talking, will you? 停止讲话，好吗？ Pass me the pen, will you / won’t you? 把这支钢笔传给我，好吗？ Don’t be late again, will you? 不要再迟到了，行吗？ Let us help you, will you? 让我们帮助你，好吗？ Let’s have a rest, shall we? 咱们休息一会儿，行吗？null用法说明： 1. 祈使句的反意疑问句，若前面是否定结构，则附加问句只能用 will you。若前面是肯定结构，附加问句用 will you，也可用 won’t / would / can / can’t you 或 shall we 等，它形式上是反意疑问句，但并不表示正式的疑问句，也不表示反意，而是表示邀请或表示请求。如： Close all the windows, will you / won’t you? 把所有的窗户都关上，好吗？ Don’t go to the park by bus, will you? 别乘公共汽车去公园，好吗？null2. let’s 用于提出建议并包括对方时，其附加问句用 shall we。let us 表示征求对方许可，其附加问句用 will you。let + 第三人称时，其附加问句用 will you。这种反意疑问句往往用来表示进一步征求对方的 意见 文理分科指导河道管理范围浙江建筑工程概算定额教材专家评审意见党员教师互相批评意见 ，使口气变得客气、委婉一些。如： Let’s go to see the pandas, shall we? 咱们首先去看熊猫，好吗？ Let us wait until 5:00, will you? 让我们等到5点，好吗反义疑问句常见考点反义疑问句常见考点1. 若陈述部分含有seldom, hardly, never, rarely, few, nothing, nowhere等否定词或半否定词，其反意疑问句部分要用肯定式。如： Dick rarely got drunk, did he? 迪克很少喝醉，是吗? He seldom comes to see you, does he? 他很少来看你，是吗? 但若陈述部分含有带否定前缀的词，反意疑问句仍用否定式。如： It is unfair, isn’t it? 这不公平，不是吗? It is impossible, isn’t it? 那是不可能的，是吗?null2. 若陈述部分的主语为somebody, someone, everyone, everybody, no one, nobody等复合不定代词，其反意疑问句的主语在正式文体中用he，在口语或非正式文体中通常用they。如： Nobody was hurt, were they? 没有一个人受伤，是吗? 当陈述部分的主语是 something, anything, nothing, everything等复合不定代词时，其反意疑问句的主语要用it。如： Nothing is important, is it? 没有什么重要的，不是吗? Everything was going well, wasn’t it？一切都很顺利，是吗？null3. 若陈述部分含有动词 have，则应注意：若为助动词，反意疑问句也用have；若表示“所有”，反意疑问句可以用have，也可以用do；若表示“吃”、“玩”等意思，反意疑问句要用do，不能用have；若用于have to，则通常用加助动词do的形式，不过有时也可用have(尤其是表示特定行为时)。如： He has a lot of money, hasn’t [doesn’t] he? 他有许多钱，是吗？ He doesn’t have any money, does he? 他没有钱，是吗? He has supper at 5, doesn’t he? 他5点吃晚餐，是吗? He often has to get up early, doesn’t he? 他经常要早起，是吗?null4. 若陈述部分含有情态动词，则情况比较复杂：在通常情况下，当陈述部分含有情态动词时，反意疑问句会重复前面同样的情态动词；若含有must，则反意疑问句可能用 mustn’t或needn’t(表示“必须”或“有必要”时)，也可能根据must后的动词形式来确定(当must表示推测时)。如：