loading考点3：情态动词：
表示说话人的情感与态度，不能单独作谓语，只能和实义动词原形一起构成谓语，无人称和数的变化。(1). 常用的情态动词一览表 原形 may can must have to shall 过去式 might could _____ had to should 词义 可以，或许 能够，可以 一定/必需 不得不 应该 句型变化：否定句一般在其后加not, 一般疑问句将其提到句首。 You may take a walk after supper. (肯定) →You may not take a walk after supper. (否定) →May I take a walk after supper? (一般疑问) I could swim at the age of seven. (肯定) →I couldn’t swim at the age of seven. (否定) →Could you swim at the age of seven? (一般疑问) We must arrive home before 10:00. (肯定) →We needn’t (don’t have to) arrive home before 10:00. (否定) →Must you arrive home before 10:00? (一般疑问) Tom had to go home on foot last night. (肯定) →Tom didn’t have to go home on foot last night. (否定) →Did Tom have to go home on foot last night? (一般疑问) Students should be allowed to play computer games. (肯定) →Students shouldn’t be allowed to play computer games. (否定) →Should students be allowed to play computer games? (一般疑问) 注意：need 作情态动词只用于疑问句和否定句中。 →Need I close all the windows? (一般疑问) →You needn’t close all the windows. (否定) You had better stay at home. (肯定) →You had better not stay at home. (否定) need _____ 需要 had better _____ 最好 (2). 情态动词表推测：部分情态动词可以用来表示推测，推测的可能性由小到大为：
can’t (不可能) →might→may (可能), →could → can (可能)，(can用于疑问句)→must (一定是)。
The man under the tree can’t be John. He went to London with his parents yesterday. (can’t用于否定句的推测)
那个树下的男人不可能是约翰，他昨天和父母亲去了伦敦。
He may know the way to the post office. I am not sure. 他可能知道去邮局的路，但我不肯定。 I saw a girl with long hair in our classroom. Who can she be? 我看见教室里有个长头发女孩，可能是谁？
The notebook must be Li Ming’s. His name is on the first page. 这笔记本一定是李明的。他的名字在第一页。 (3). 难点。
A. can(could)与be able to
can只用现在时，过去时用could。此两词不用于其他时态。be able to可用于任何时态。 She can (is able to) drive a car. 她能开车
He could (was able to) play the piano at the age of ten. 他10岁时能弹钢琴。
I will be able to ride a bike in a week. (不能用can/could) 一个星期内我就会骑自行车。 B. must与 have to
must主观因素决定。have to外界条件决定。
I think I must finish my work today. 我想我必须今天内完成我的工作。
The last bus has gone. I have to walk home.最后一辆公交车走了，我必须要走路回家了。 C. must 表示“必须”时否定形式为needn’t或don’t have to，而不是mustn’t。mustn’t表示禁止。
They needn’t have breakfast so early. 他们不需要这么早吃早餐。 You mustn’t talk in class. 你禁止在课上讲话。 D. 几个情态动词否定形式的意义:
might not/ may not (可能不) can’t/ couldn’t (不可能) mustn’t (禁止)
There are many stars in the sky. It may not rain tomorrow.天上有很多星星，明天可能不下雨。 He had a big meal just now. He can’t be hungry now. 他刚吃了一大餐，现在不可能饿。 The children mustn’t play football in the street. 孩子们禁止在街上踢足球。 E. 几个情态动词在一般疑问中的回答。
–May I smoke here? 我可以在这里抽烟吗？
– Yes, you may. 是的，你可以。/ –No, you mustn’t/can’t. 不，你禁止抽烟。 –Can you come to see me tomorrow? 你明天能来看我吗？ –Yes, I can. 是的，我可以。/ – No, I can’t. 不，我不能。 –Must he go now? 他一定要走了吗？
–Yes, he must. 是的，他必须走。/ No, he needn’t (doesn’t have to). 不，他不需要。 –Need I finish my homework today? 我需要今天完成作业吗？
–Yes, you must. 是的，你必须。/ –No, you needn’t. 不，你不需要。 ( ) 6. –Where is our head teacher, Mr. Black?
–He _________ be in the office. I saw him there a minute ago. A. can B. may C. might D. must ( ) 7. –Is that your best friend Simon?
–No, it __________ be him. He flew to Hong Kong yesterday. A. mustn’t B. may not C. can’t D. needn’t ( ) 8. –_________ I borrow these magazines?
–Sorry, only the magazines over there can be borrowed. A. Must B. Would C. May D. Need
( ) 9. –Must I ________ my camera, Lily? –No, you _______. I’ll take one myself. A. take, mustn’t B. take, needn’t C. bring, needn’t D. bring, mustn’t ( ) 10. –________ you swim? –Yes, but I am not a good swimmer. A. Can B. May C. Need D. Must
( ) 2. –Must I answer this question in English? –No, you ________. A. mustn’t B. needn’t C. can’t D. shouldn’t ( ) 13.We _______ wait for her because she said she would not come. A. needn’t B. should C. must D. mustn’t
( ) 14. I can’t take part in the sports meeting because of my broken leg. I _______ stay at home. A. have to B. must C. can D. may ( ) 15. –Look at that girl! Is she Susan?
–No, it _________ be her. She has gone back to her hometown. A. shouldn’t B. mustn’t C. can’t D. needn’t 循环二
( ) 1. –______ I use your telephone? –Sure. Here you are. A. May B. Must C. Should D. Could
( ) 10. –Excuse me, where are we going to have our class meeting? –I’m not sure. Ask our monitor. He _______ know. A. can B. can’t C. may D. shall
( ) 11. –What will the weather be like tomorrow? –It ______ be rainy, cloudy or sunny. Who knows? A. must B. might C. shall D. should