情态动词的语法特征1）情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。

2）情态动词除ought和have外，后面只能接不带to的不定式。

3）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-So4）情态动词没有非谓语形式，即没有不定式，分词，等形式。

1、表示能力:can /could , be able to （+do）1）c an和be able to的区别：观察以下各句，可知can只能用于________ 和__________ ；be able to可用于各种时态。

eg:① I can /am able to speak En gliS他能说英语。

②He could/ was able to eat four pieces of bread when he was young.③They will be able to finish the housework soon.2）C an/couldyou+动原+其它？表示征求对方意见或提出请求，表示委婉语气, 但在这个句型里could 比can更委婉。

但要注意它的回答用can不用could.Eg: ---Could you help me ?---Yes, I can.2、表示许可:may/might, can/coul（但一定要注意：以may开头的疑问句的否定—例如：---May I come in- Yes, you may. / No, you can ' t = No ,you mustn3、表示必须、必要:must, have to表示 _________ ；needn 表示Eg: You must/ have to fin ish the wo你必、须完成这个工作。

1）观察以下句子，我们可知must表示说话人的______________ ; have to表示____________ 。

Eg:① I must go home我必须回家；② He has to give up smoking because of badly cou 因h为咳嗽，他不得不戒烟。

2）观察以下句子，我们可知mustn '表示_______ ，译为__________ ；don' t haveto译为。

Eg:① Youmustn 'beat her.你不准打她。

② -Must I finish my homework n —/Yfes, you must ./ Nyou needn=youdon' t have to、我必须现在完成作业吗？--是的，你必须完成。

/不，你不必了。

4、表示推测: must, can, could , may, might.Eg:① You run for hours, you must be very ti 你跑了几个钟，你一定很累了。

②It can 'be John. He has gone to the U不可能是John,他已经去了英国。

③—Vho can it be?——It may/could/might be Jack. It looks like him.-可能是谁呢？--可能是Jack,看起来像他。

观察以上各句总结：肯定推测_______ 译为________ ;否定推测___________ 译为；疑问推测有个译为；可能性推测用。

及时训练并归纳最常考情态动词的用法：1 、---Would you like to go fishing with me ? ---Yes,/_ 。

2、---May I put these things here? ---Yes, _________ / No, ___________3、---Must we hand in our homework today? ---Yes _________ / No, ________4、---Look! Some one is coming. It __________ be our class teacher.（用must/ca n/could/may/mig填空）---It _ be him. He has gone to Beiji ng.1. 中考怎么考？丨1. —Look! I ' ve chosen so manhthe-Do you know all these should _______ （付款）in US dollars? （pay ）2. — Shall we take a taxi?— No, we _____ .It ' s not far from here.A. can ' tB. mustn 't C, shouldn ' t D. needn 't3. —Whose T-shirt is this?—It ______ be Joh n's. It's much too small for him.A. mayB. mustC. can'tD. should n't4. —What should we do about the trash —It （65） ___ （必须带走）when you leave.（take ）2. 中考考什么？1. 情态动词的用法：情态动词后 +动词原形 例：You must finish the work.否定句：情态动词 +not 例: He can not carry the box.2. can 能力，许可”例：He can swim now.（能够）can ' t =cannot =can 不能” 例: “ Hecan"swim now.不能）could ①could 是 “ ca 的过去式 ” 例: He could swim three years ago.②could 还可以表示客气委婉的语气或请求”，用在疑问句中。

回答时用can 。

例: Could Jimlend me his bike? -------------------------- Yes, he can.★ can 和be able to 在表示 能力”上意思相同，差别不大。

can 只有现在和过去两种 形式，而be able tc 有更多的时态形式例: No one can do it. = No one is able to do it.I ' m sorry I haven ' t baenwelgour letter.3. may 可以许可，”例：May I borrow your ruler?may not 也许不 ” 例: Today Jim may not come to our party.01. I _______ follow you. Would you please repeat it?A. can ' tB. mustn ' tC. needn 'tD. shouldn ' t02. T forgot to bring my dicti on ary. Could I use y —Yfe?, you _____ .A. canB. mustC. couldD. should03. .--Pauline has lost her pho —No. It ' 由iagh e r ________ hear it.A. mustB. canC. mayD. shall04. . Finish your homework first, then you ' ll _______ watch TV for an hour.A. canB. be able toC. able D could05. . — ______ I have lunch now, MotMNb. You must wash your hands first.A. WouldB. MayC. Ought to06. .— Have you decided where to go for your summer vacatio n —Not yet. We goto Qin gdao . It'sa good place for vacati on. A. may B. n eed C. must07. . ________ you please give me a hand? The box is too heavy.A. ShouldB. CouldC. MustD. Need4. must 必须 ” 例: You must finish the work today.must not =must n 不可以，“不应该 ” 例: Youmustn 'lend the book to some one else.★ must 和 have to 都表示必须，must 强调主观看法，have to 强调客观事实需要。

must 只有现在和过去两种形式，而 have to 有更多的时态形式。

We will have to finish the work.（用于将来时用 have to 而 must 则不能）5. need 必'要，必定 ” 例: You need start the work now. needn ' t =need i 不必” 例： Weneed ' h u rry.★ need 还用作实意动词，有各种变化例: He needs to know it.（肯定句）例: 原因） I must fin ish the work.（主观上想完成） My teacher will come to my home, so I have to clean my r / -4y 师要来是客观He doesn' t need to know（否定句）Does he need to know it （ 一般疑问句）6. have to 动词原形，表示 必须做一-。

例：He has to finish his homeworkat first. He doesn havte to finish hishomework at first.The boys have to finish their homework at fiiThe boyadon ' t havefitoish their homework atfirst.01. —Dad, must we wait until the light becomes green —Yes, rm afraid we .That's the traffic rule.A. canB. mayC. have toD. n eed02. —Excuse me, may I keep the book a little Ion gerSorry. You _______ return ittoday.A. mustB. mustn 'tC. canD. can 't03. Children ________ sit in the front seat of a car. It ' s too dangerous.A. needB. needn ' tC. mustD. mustn 't04. We _______ pay to get into the con cert. It's free.A. can 'tB. mustn 'tC. might notD. don ' t have to7. 情态动词的一般疑问句的回答有变化Can he swim? Yes, he can. No, hecan. tMay I watch TV now? Yes, you may （can ）. No ,youmustn '或t.can. tMust I finish the work nowYes, you must. No, youneedn. =t oudon ' t have to01. —Must I water the flowers now, mt —Jb, you _____ . You _____ do it later.A. mustn ' t; mustB. mustn ' 也 maC. needn ' t; mayD. needn ' t; must 02. —May I take this magaz ine out of the read ing roc —?）, you ________________ . You read it inhere.A. mightn 'tB. won 'tC. needn 'tD. mustn 't 03. —Can I park my car in front of the build —g?, you ____________________________________________ .A. won'tB. can'tC. need n'tD. could n't04. —May I play computer games, Mo —No, you ____________ .A. don ' tB. can ' tC. wouldn ' tD. won ' t05. —May I smoke here —No, you _______ . This is a no-smok ing room.A. needn 'B. mustn 'C. couldn 'D. wouldn ' t例：①You must be ill. I ca n see it from your fac 定是病了，表示对现在的推测 ）② John is abse nt. He may\might be 也许是病了，表示对现在的推测）③ The guitar could bem '可能是，表示对现在的推测）④ He can ' t ibethe room.（不可能是，表示对现在的推测）01. — Who s singing in the gard —n? __ be Mr. Brown. He always practices singingat this time.A. mustB. can ' tC. need02. Ts the man over there Mr. BrownI? ______ him. He has gonedBrazil to watchthe 2014 FIFA World Cup.A. may notB. can ' t beC. shouldn ' tD. mustn ' t8. 情态动词表示猜测情态动词 ① m ust② m ay \might ③ c ould ④ c an 推测 must +动词原形 may\might 动词原形could 动词原形 can '动+司原形 意思也许是 可能是---不可能是03. —Bob, where is Lin da?She _______ be in the libraryt bam not sure.A. mustB. mayC. n eedD. has to04. —Where are you going this mor rt hWe _____ go to Xiame n, but we're not sure.A. n eed n ' tB. mustC. mightD. must n't05. Ts Mr Brown driving he—? ' m not sure. He _______ come by train.A. mayB. shallC. n eedD. must9. had better 动词原形，表示最好做---”。