情态动词用法补充■must的两种用法1. 表示必要性可强制性，“必须，应当”。其过去式可用had to；否定式可用needn’t或don’t have to (不必) 等；mustn’t是may的否定式，意为“不允许，不可以，千万不”，表示禁止。2. 表示坚持，“硬要，偏要，一定要”。如：1. Children under 12 years of age in that country ________ be under adult supervision when in a public library. (上海卷)A. must B. mayC. can D. need【分析】答案选A。must表示强制性，意为“必须、应当”。2. —Who is the girl standing over there?—Well, if you ________ know, her name is Mabel. (天津卷)A. may B. can C. must D. shall【分析】答案选C。must表示坚持，“一定要、非得”。3. Johnny, you ________ play with the knife, you ________ hurt yourself. (全国卷)A. won’t; can’t B. mustn’t; may C. shouldn’t; must D. can’t; shouldn’t【分析】答案选B。mustn’t(千万不)表示禁止；may表示可能性。句意为“你千万不要玩刀子，可能会弄伤自己的。”注：must与have to的比较：have to却有更多的时态形式；must强调主观看法，而have to更强调客观要求；询问对方意图时用must, 即：Must I…?　■shall的三种用法①表示说话人的意图。主语可以是任一人称，表示说话者给对方的承诺、决心、警告、威胁等；②表示强制。用于法令、条约、规章中，意为“必须，应该”；③征求对方意见。用于主语是第一、三人称的疑问句中，意为“要不要…？”“…好吗？”如：1. — Excuse mc, but I want to use your computer to type a report. —You ________ have my computer if you don’t take care of it. (湖南卷)A. shan’t B. might not C. needn’t D. shouldn’t【分析】答案选A。shall表示说话人给予对方以警告。2. “The interest ________ be divided into five parts according go the agreement made by both sides,” declared the judge. (重庆卷)A. may B. shouldC. must D. shall【分析】答案选D。shall表示条约的规定，意为“必须”。句意是：法官宣布“根据双方所订的协约，利息必须分成五份。”3. It has been announced that candidates(应考者) ________ remain in their seats until all the papers have been collected. (上海卷)A. can B. willC. may D. shall【分析】答案选D。在规章中告诫应考者，在收完所有试卷前“必须”留在教室里。[1][2][3]下一页 说明:引用此文请注明出处,并请保留该文章链接地址,谢谢~~■should的用法should除表示推测外，还可表示责任或义务，“应该，应当”；用于条件句表示“万一”；还可表示“竟然”等。如：1. I often see lights in that empty house. Do you think I ________ report it to the police? (广西卷)A. should B. may C. will D. can【分析】答案选A。我常发现那座“空房有灯”这种异常现象，所以问你我“该不该”将此现象报告警察，因此，用表示责任或义务的should。2. I ________ pay Tracy a visit, but I am not sure whether I will have time this Sunday. (浙江卷)A. should B. might C. would D. could【分析】答案选A。should表示一种责任或义务，“应该”。■will和would的用法①表示意志，愿望和决心，意为“愿意”，可用于条件句。如：If you will allow me, I will see you home. 如果你愿意，我送你回家。②表示请求。可用Will / Would / Won’t / Wouldn’t you…?“请…”“…好吗?”但回答时不用would。如：Will you post the letter for me, please?请帮我把这封信寄出去好吗？③表示习惯，仅用于陈述句。如：She will listen to records, alone in her room, for hours. 她常常独自一人在自己的房间里呼唱片，一听就是半天。④表示真理或事物的品质，还可表示“能够”。如：Oil will float on water. 油能浮在水面上。Accidents will happen. 事故总是难免的。That container will hold a gallon. 那容器能够装一加仑。The wood will not burn. 这木材无论如何也烧不着。上一页[1][2][3]下一页 说明:引用此文请注明出处,并请保留该文章链接地址,谢谢~~■had better和would rather的用法两者后均接动词原形，否定式在原形前加not；在否定问句和反意问句中可用hadn’t / wouldn’t。对长辈或上级说话时，不宜使用。had better在口语中常说成’d better, 甚至better。如：1. —Shall we go skating or stay at home?—Which ________ do yourself? (全国卷)A. do you rather B. would you rather C. will you rather D. should you rather【分析】答案选B. would rather do sth. 意为“宁愿做某事”；其中would不可用should或其它助动词代替；其疑问式是将would提到主语前。2. If you are planning to spend your money having fun this week, better ________ it—you’ve got some big bills comi