1、Period three Grammar: Review of modalsStep 1. Revision:Revise the language points of the passage we have learned.Step2.Explanation1. 情态动词有:can, could, may, might, must, have to, dare, need, shall, should, ought to, will, would, had better.2.情态动词的语法特征:1）情态动词没有人称，数的变化，即情态动词第三人称单数不加-s。 2）情态动词除ought 和ha
2、ve 外，后面只能接不带to 的不定式。3）情态动词没有非谓语形式，即没有不定式，分词，等形式。4)部分有过去式的变化3. 情态动词can, could, may, might, must 表示”推测”的用法:情态动词中的must, can, could, may, might都表推测。其中must的可能性最大，can / could次之，may / might最小。具体用法如下can / could表推测的用法:1）can表示推测“可能性”时，意为“可能，也许，大概”2)“can +动词原形” 表示对现在的状态和事情的推测,如：He can be a doctor. He can like
3、English. 3) “can be doing” 表示对现在正发生的事情的推测,如： He can be playing basketball on the playground4）can + have done，表示对过去发生的动作进行推测。He can have gone to Shanghai .他可能去上海了。Its so late. Where can she have gone? 天晚了，她可能去哪儿了呢？could 表示比can更委婉的语气（不表示过去式），比can更加不肯定。 could have done 本能做但未做，表虚拟语气 I could have done it
4、 well，but I wasnt so careful then .2. may和might表推测的用法:（1） may, might表示推测“可能性”时，意思是“可能”、“也许”He may / might be American. = It is possible that he is American.他可能是个美国人。注：might不表示过去时态，只是语气上比may更委婉，表示的可能性更小。（2）may, might表推测时，可以用于否定句，意思是“可能不、也许不” ，但不用于疑问句。He may / might not be at home. 他也许不在家。3）may, might
5、可以推测现在正在发生的动作或过去发生的动作。He may / might be sleeping now. The boy may / might not be watching TV at home. 这个男孩可能没在家看电视These students may / might have seen the film before.（过去）这些学生以前可能看过这部电影。3.must表示推测的用法:1） must在肯定句中表示较有把握的推测.“肯定，必定，一定.”2） “must +动词原形” 表示对现在的状态和事情的推测,如： You have worked hard all day. You
6、 must be tired. He always studies English. He must like English.3) must be doing 表示对现在正发生的事情的推测,如： He must be playing basketball on the playground.4) 表示对已发生的事情的推测时，must 要接完成式。即：must +have +doneI didnt hear the phone. I must have been asleep. 我没听见电话铃响。我一定是在睡觉。5） must have been doing 表示对过去某时正发生的事情的推测,
7、 如：-Why didnt you answer my phone call? -Well, I must have been sleeping, so I didnt hear it. 6） 否定推测用cant。 He must know my address. 他肯定知道我的地址。（一定） He cant know my address. 他肯定不知道我的地址。（一定不）Can he know my address? 他知道我的地址吗？（询问可能性）7).在反意疑问句中，当附属部分含有表示推测意义的must时，疑问部分的助动词应与must后面的动词在非推测情况下的用法保持一致。 He mu
8、st be a worker, isnt he? （现在）他准是个工人，是吗？You must have learned English for many years, havent you? （完成时）你一定学了好多年英语，是吗？比较：It must have rained last night, didnt it? （过去）昨晚一定下雨了，是不是？He must have arrived by yesterday morning, hadnt he?Step3.Exercises: Do the activities on Page 75and Page76(1.) Ask the stu
9、dents to do these sentences individually, then check with their partners.(2) Ask the students to answer the questions, reading the complete sentences.(3)The teacher tells the students the correct answers.Step4. should , could, would的用法should的用法：1 “表示征询” ，用于第一人称的疑问句中，语气较委婉； Why should I meet them?2 表
10、示 “义务、应该、建议” ，可用于多种句式； You should hand in your exercise book.3表示 “虚拟，委婉的批评” ，用于完成时的肯定句 中，表示过去该做而没做的事；用于否定句中，表示过去不该做而做了的事。You should have handed in your homework beforeyou went out to play.（实际上没交）could的用法：1 表示过去的“可能性” 或“能力” Before liberation, few workers could support their family.(表能力) He could be v
11、ery naughty when he was young.(表可能性)2 比较委婉客气地提出请求或陈述看法等，时间上与can没什么差别。Could you lend me your bike?would的用法:1表示“意志” “意愿”，用于各种人称，指过去将来 I promised that I would do my best.2表示“请求”，用于第二人称的疑问句中，比 will 更客气 Would you like a banana?3表示“习惯”，指过去习惯，比used to更正式，常表示动作,不涉及现在。 I would take a walk when I was a studen
12、t.4 用于固定习语中，如：would rather, would sooner, would.mind等Step5. Exercises: Do the activities on Page 78and Page79(1.) Ask the students to do them individually, then check with their partners.(2) Call back the answers from the whole classstep 6.情态动词与高考试题1.-Shall we go skating or stay at home? -Which _ do
13、? A. do you ratherB. would you rather C. will you rather D. should you rather2.-Shall I tell John about it? -No, you _. Ive told him already.A. needntB. wouldnt C. mustntD. shouldnt3 -Dont forget to come to my birthday party tomorrow. -_.A. I dont B.I wont C. I cantD. I havent 4 I thought you_ like
14、something to read. So I have brought you some books. A. ought B. might C. would D. must5. That man must be Sarahs husband.-No, he_ be her husband. She is still single. A. cant B. mustnt C. may not D. ought to6. Peter _come with us tonight, but he isnt very sure. A. must B. may C. can D. will7. Susan
15、 refuses to marry Jack now. She _her mind.A. must change B. should have changedC. must have changed D. would have changed (1.) Ask the students to do them individually, then check with their partners.(2) Call back the answers from the whole classstep 7.Homework Finish the exercises on P 121 and 122 in your workbook
