1、Grammar Focus 情态动词情态动词 may,can,must,need may 可能；可以可能；可以 may not 可能不可能不 can 能；可以能；可以 cant 不能；不可能不能；不可能 must 必须；一定必须；一定 mustnt 不准，不允许不准，不允许 need 需要需要 needt 不必，不需要不必，不需要+动词动词()原形原形(能能)表示能力表示能力 He can speak a little English.Can you fly?表示请求或允许表示请求或允许 Can I help you?表示猜测表示猜测 That can not be our English t
2、eacher,because she has gone to Shanghai.表请求时 could语气更委婉，主要用于语气更委婉，主要用于疑问句，不可用于肯定句，答语应用不可用于肯定句，答语应用can.Could I come to see you tomorrow?Yes,you can.（否定答语可用（否定答语可用No,Im afraid not.）表能力时 could 是是 can 的过去式。的过去式。表示请求或允许表示请求或允许:May I go home，please?以以may（表许可或请求）开头的一般疑问句（表许可或请求）开头的一般疑问句,肯定回答肯定回答用用may，否定回答用
3、，否定回答用mustnt或或cant.表示猜测（可能）表示猜测（可能）:You may be right.No,you _ (可以可以)Yes,you may.might为为may的过去式，的过去式，语气较为婉转客气或更加不肯定。语气较为婉转客气或更加不肯定。You might be right.mustnt/you cant.表示推测表示推测“肯定，一定肯定，一定”:表示命令表示命令“必须必须”:You must come early tomorrow They must be at home.The light is on.(必须必须)(禁止禁止)否定时表示否定时表示“禁止禁止”:You
4、mustnt smoke here.must开头的疑问句，开头的疑问句，其否定回答通常用其否定回答通常用 dont have to 或或neednt。而不用。而不用mustnt -Must I finish my homework first?-Yes,you must.-No,you dont have to/neednt.1.-Must I come before eight oclock?-No,you _.”A.cant B.dont C.mustnt D.neednt2.-Must I finish all the work before I leave?-Yes,you _.”A.
5、must B.can C.mustnt D.neednt3.You _ be quiet when you are in a library.A.may B.can C.will D.must（表命令）比较比较 You may not smoke here(不可以不可以)语气轻语气轻 You cant smoke here（不能）重（不能）重 You mustnt smoke here（决不可）最重（决不可）最重 既可以做情态动词既可以做情态动词,也可以做实意动词。也可以做实意动词。情态动词情态动词(need do sth)I need buy a big house.(需要需要)He nee
6、d drive me home.Need I buy a big house?-Yes,you must.-No,you neednt/dont have to.(不必要不必要)实意动词实意动词(need to do sth)He needs to buy a big house.Do I need to buy a big house?-Yes,you do./-No,you dont.had better do sth 意为意为“最好最好”，表示建，表示建议和劝告，否定式为议和劝告，否定式为had better not do sth.，后面跟后面跟动词原形动词原形。You had bett
7、er go to see a doctor.Youd better not stay here.(最好最好)(必须必须)have to 表示客观因素表示客观因素We are very glad at the party,but mother is ill,so we have to leave now.must 表示主观因素表示主观因素We must study hard to find a good job for ourselves.(必须必须)1.It rained heavily,so we _ stay at home watching TV all day.A.could B.ha
8、d to C.must2.May I take the book out of the reading room?No,you cant.You _ read it here.Its the rule.A.must B.would C.may 3.Dad,may I watch TV?No.You _ finish your homework first.A.must B.can C.may 4.Bob,shall we go and meet our new classmate?Sorry.Im busy now.But you _ ask David to go with you.He i
9、s free Aneed Bmay Cmust4.Could I borrow your dictionary?Yes,of course you _.A.might B.will C.can D.should5.You _ return the book now.You can keep it till next week if you like.A.cant B.mustnt C.neednt D.may notC C 6.Johnny,you _ play with the knife,you _ hurt yourself.A.wont;cant B.mustnt;may C.shou
10、ldnt;must D.cant;shouldntB 7.-Will you stay for lunch?-Sorry,_.My brother is coming to see me.A.I mustnt B.I cant C.I neednt D.I wont8.-May I pick a flower in the garden?-_.A.No,you neednt B.Not,please.C.No,you mustnt D.No,you wontB C 9.-Must I drive to his house and pick up the children?No,.A.you s
11、houldnt B.you might not C.you neednt D.you mustntC 10.There is someone knocking at the door.it be Tom?A.can B.must C.should D.ought toA 1.Who is the man over there?Is it Mr Li?No,it _ be him.Mr Li is much taller.A.mustnt B.may not C.cant D.neednt2.Could I look at your pictures?Yes,of course you _.A.
12、could B.can C.will D.might3._you pass me a pen?Id like to write down the telephone number.A.Need B.Could C.Must D.Should4.May I go to the cinema,Mum?Certainly.But you _ be back by 11 oclock.A.can B.may C.must D.need5.Susans parents have bought a large house with a swimming pool.It _ be very expensive.A.must B.can C.mustnt D.cant6.You _ go and ask Meimei.She _ know the answer.A.must;can B.must;may C.need;can D.can;may7.If you are in the zoo,remember not to touch or go near the animals.Although some of the animals are cute,you _ leave them alone.A.must B.will C.may D.can
