1、Unit 2 Healthy eatingPeriod 4 语法专题课学习目标1.Grasp the grammatical rules of ought to,need,dare,had better in this unit.2.Learn to use the modal verbs in real situations through self-study and practice.学习过程一、语法聚焦(一)情态动词的基本用法:1.ought to(1)Humans ought to (should) stop polluting nature.人类应该停止污染大自然了。(2)Pric
2、es ought to come down soon.价格可能会很快下跌。(3)You ought to have come earlier.你本该来得早一点儿。(4)They ought to go and see Mary tomorrow,but I dont think they will.他们明天按理说应该去看看玛丽,但是我认为他们不会去的。(此句不宜用 should)(5)He ought to go now,oughtnt he?他现在该走了,是吗?ought to 用法小结:(1) (2) (3) (4)ought to 与 should 的区别(5)ought to 的否定形
3、式为 2.need(1)Need you go so early?你需要这么早走吗?Yes,I must. 是的,我必须走。/No ,I neednt.不,不必。(2)You neednt have bought it.你没有必要买( 它)的。(但已经买了 )(3)You dont need to be so worried.你不必如此担心。(4)Do I need to say my telephone number again?我还需要再说一遍我的电话号码吗?need 用法小结:(1) (2)need 后接完成时表示 “ ”。 (3)need 用作实义动词时 , 3.dare (1)My
4、younger sister dare not go out alone.我妹妹不敢单独出去。(2)If you dare cheat in your exam,I will give you some punishment.如果你(们) 敢在考试中作弊,我就惩罚你(们) 。(3)She dares to go there alone.她敢一个人去那里。(4)He did not dare (to) leave his car there.他不敢把车停放在那里。dare 用法小结:(1)dare“敢;敢于 ”,dare 用作情态动词时 ,具有四个特点:第一, 第二, ;第三 , ; 第四 ,
5、。 (2)dare 用作实义动词时 , 4.had better(1)Youd better go to see a doctor.你最好去看看医生。(2)Youd better not disturb him.你最好别去打扰他。(3)How had we better go there?我们最好怎么去那儿呢?(4)Hadnt we better take an umbrella?我们是不是带把雨伞比较好?had better 用法小结:(1) (2)如何构成否定句和疑问句: (3)在否定疑问句或反意疑问句中 (二)情态动词表示推测的句型归纳must(一定,肯定),may/might (可能,
6、也许),can/could (可能,通常用于否定句和疑问句中 ),should/ought to(应该)常可用来表示推测。1.一般时推测:主语+情态动词(not )+动词原形。(1)He must come from the USA.=It is certain that he comes from the USA.他肯定是美国人。(2)He may/might/could come from the USA.= It is possible that he comes from the USA.他可能(大概、也许)是美国人。归纳: 2.进行时推测:主语+情态动词(not )+be doing
7、 sth.(1)They must be organizing a great performance.他们一定正在组织一次大型的演出活动。(2)He should be working now.他现在应该在工作。归纳: 3.完成时推测:主语+情态动词(not )+have done.“情态动词+have done ”可表示 “推测 ”“责备 ”“怀疑 ”等多种意义。(1)You shouldnt have told her the truth.你本不该告诉她真相的。(2)The ground is wet.It must have rained last night.地面很湿,昨晚肯定下雨了
8、。(3)The ground is very dry,so it cant have rained last night.地面很干,昨晚不可能下过雨的。(4)She neednt have come yesterday.她昨天本不必来的。(5)Its late.He might have gone to bed.时间不早了,他也许已经睡觉了。(6)You could have given more attention to it.你本可以多关心它一点的。情态动词表示推测用法小结:(1)should/ought to have done (2)shouldnt/oughtnt to have d
9、one (3)must have done (4)cant/couldnt have done (5)neednt have done (6)might/may have done (7)could/might have done 二、语法聚焦自测1.用 should,must,can,need,had better 的相应形式填空(1)You look tired.You go to bed now. (2)My mother cooked a lot of food for me.She has been cooking all the morning.She be tired now.
10、(3)I have just eaten a lot of food for lunch.You be hungry now. (4)The floor is clean.You sweep it. (5)I can manage the shopping alone.You come with me. (6)You not disturb him. 2.I searched for my wallet in the bag but it wasnt there.I thought I it at home. A.left B.have leftC.might have leftD.can h
11、ave left 3.I asleep because it took me a long time to realize that the telephone was ringing. A.could have fallen B.should have fallenC.must have fallenD.mustnt have fallen课后提升挑战一 小试牛刀单项填空1.-What sort of house do you want to have?Something big?-Well,it be bigthats not important. A.mustnt B.neednt C.
12、cant D.wont2.Thank you for all your hard work last week.I dont think we it without you. A.can manage B.could have managedC.could manage D.can have managed3.Tom ought not to me your secret,but he meant no harm. A.have told B.tells C.telling D.having told 4.I wonder how he that to the teacher.(易错题) A.
13、dare to say B.dare saying C.not dare say D.dared say 5.I didnt see her yesterday.(易错题)Of course,you ,because she had gone on a trip. A.cant B.may not have C.cant have D.mustnt have 根据提示翻译句子6.你敢在夜晚穿过森林吗?(dare )7.你本不应该泄露这个秘密的。(ought to)挑战二 典题在线1.Ive ordered some pizza,so we worry about cooking when we
14、 get home tired. A.cant B.dare not C.neednt D.may not2.I prepared all kinds of food for the picnic.Do you mean we bring anything with us ? A.cant B.mustnt C.shant D.neednt3.My book,The House of Hades,is missing.Who have taken it ? A.need B.must C.should D.could4.You neednt take an umbrella.It isnt g
15、oing to rain.Well,I dont know.It do. A.might B.need C.would D.should5.Why are your eyes so red?You have slept well last night. Yeah,I stayed up late writing a report.A.cant B.mustnt C.neednt D.wont6.I myself more it was a perfect day. A.shouldnt have enjoyedB.neednt have enjoyedC.wouldnt have enjoye
16、dD.couldnt have enjoyed7.Harry is feeling uncomfortable.He too much at the party last night. A.could drink B.should drink C.would have drunk D.must have drunk8.The children lost in the woods;otherwise,they would have been at the lakeside camp as scheduled. A.must have got B.must get C.should have go
17、t D.should get课后作业1.Master what we have learned today.2.Correct the mistakes in the paper.参考答案学习过程一、语法聚焦(一)1.(1)表示义务或职责,提出要求,即人们应该去做的正确的事或好事 ,意为 “应该 ”。(2)表示很大的可能性(通常指的是一种合乎逻辑的可能性),意为 “应该,可能 ”。(3)ought to 后跟完成时,其肯定句表示 “过去本应该做某事而未做 ”;其否定句则表示 “过去不该做某事但做了 ”。(4)一般说来,两者可换用,只是 ought to 语气略强。另外,表示出于法令规则、行为准
18、则、道德责任等客观情况而 “应该 ”做某事时,一般应用 ought to;若用 should 则含有个人意见,强调主观看法。(5)ought not to 或 oughtnt to。2.(1)用作情态动词,意思是 “有必要 ”或 “需要 ”,无人称和数的变化 ,通常只用于否定句和疑问句中。由于用作情态动词的 need 通常不用于肯定句,所以对于以 need 开头的疑问句的肯定回答不能用 “Yes,I need.”,而常用 “Yes,I must.”来回答。(2)过去本不必做某事却做了(3)有人称和数的变化,后面要跟带 to 的不定式。3.(1)没有人称和数的变化; 没有语态的变化但有过去式(d
19、ared);不用 do,does 或 did 来构成否定和疑问结构,其一般疑问句式是把 dare 置于句首,其否定句式是在 dare 后加 not;主要用于否定、疑问及条件句中。后接动词原形(不带 to)。(2)有人称和数的变化,可用于各类句型( 肯定句、否定句、疑问句及各类从句等),其后接to do,但在否定句中,to 可省去。4.(1)had better 意为 “最好 ”“应该 ”,后接动词原形,与情态动词 should 用法相似,其中的 had通常缩略为 d。(2)构成否定句时,通常将 not 置于 had better 之后;而构成疑问句时,则通常将 had 置于主语之前。(3)在
20、had 后面加上 not。(二)1.该句型对主语当前的行为、情况或状态做出肯定的或否定的推测。注意:这里的might 和 could 不是表示过去时态 ,而表示可能性更小。注意: must 表示推测只能用在肯定句中。2.该句型对主语此时此刻正在进行的行为做出肯定的或否定的推测。3.(1)“本应该做 ”(实际上没做 ),表示说话人后悔、遗憾或责备的语气。(2)“本不该做 ”(实际上却做了 ),也表示说话者后悔、遗憾或责备的语气。(3)“肯定已经做了 ”,表示对过去发生事情的肯定推测。(4)“肯定没有做 ”“不可能已经做 ”,表示对过去发生事情的否定推测。(5)“本来不必做 ”(实际上却做了 )。
21、(6)“可能已经 ”,表示对过去发生事情的肯定推测,把握性较小。(7)“本来可以做 ”(实际上没做 ),表示说话者后悔或责备的语气。 (不可用 can 替代could 或用 may 替代 might)二、语法聚焦自测1.(1)should (2)must (3) cant (4)needn t (5)needn t (6)had better2.C 3.C课后提升挑战一1.B 2.B 3.A 4.D 5.C6.Dare you walk through the forest at night?7.You oughtnt to have let out the secret.挑战二1.C 2.D 3.D 4.A 5.A 6 .D 7.D 8.A