1、人教版初中英语七年级下册Unit4 语法指导与练习Unit 4 Dont eat in class.Unit 4语法指导与练习语法指导【祈使句】【教材原句】1.Eat in the dinning hall.2.Dont ear in the classroom.3.Dont run in the hallways.4.Dont fight.以上例句,都是 句,以 开头,其否定形式是在句首加 。(祈使,动词原形,dont)【语法透析】1.祈使句概述。 用于表达命令、请求、劝告、警告、禁止等得句子叫做祈使句。祈使句最常用于表达命令,因此也常称为命令句。祈使句因对象(即主语)是第二人称,所以通常都
2、省略主语。祈使句的动词都为一般现在时,句末则使用句号或感叹号来表示结束。例如:Go and wash your hands.去洗手。(命令)Be quiet,lease.请安静。(请求)Be kind to our sister.对妹妹要和善。(劝告)Watch your steps.走路小心。(警告)Look out!Danger!小心!危险!(强烈警告)Keep off the grass.勿踏草坪。(禁止)【试题链接】 “ exercises every day,my son.Its good for your health.”Dad often said to him.A.Takes
3、B.Taking C.Take D.To take(考查祈使句。意为“儿子,每天都要做运动“。本句式祈使句,动词用原形,故选C。)【试题链接】 up,Anna.Its seven thirty.one more minute,Mom.A.Get B.Gets C.Getting D.Got (答案A)【拓展记忆】祈使句有时把主语“You”表达出来,使对方听起来觉得柔和些。例如:You go and tell him,Chris.克里斯,你去告诉他。2.祈使句的形式。 1)肯定祈使句的表现形式:Do型动词原形(+宾语)+其他成分Please have a seat here.请这边坐。Be型Be
4、+表语(名词或形容词)+其他成分Be a good child!要做一个好孩子!Let型Let+宾语+动词原形+其他成分Let me help you.让我来帮你。2)否定祈使句的表现形式:a.Do型和Be型的否定式都是在句首加dont。例如:Dont forget me!不要忘记我!Dont be late for school.上学不要迟到。b.Let型的否定式有两种:一是“Dont +let+宾语+动词原形+其他成分”,二是“Let+宾语+not+动词原形+其他成分”。例如:Dont let him go./Let him not go.别让他走。c.有些可用no开头,用来表示禁止性的祈
5、使句。例如:No smoking!禁止吸烟!No fishing!禁止垂钓!【试题链接】 call me Wang Wang!Its my dogs name.A.Not B.No C.Dont (答案C)【拓展记忆】:a.有的祈使句,在意思明确的情况下,动词可省略。例如:This way,please.=Come this way,please.请这边来。b.若要表示请求、客气等意愿时,可以在句首或句末加上please,位于句末时please前常加逗号。3.对祈使句的基本回答。1)A:Tom,take the box to Mr.Wus office. B:肯定回答:Yes,I will.好
6、的,我会做的。 否定回答:Sorry,I cant carry it.对不起,我搬不动它。2)A:Dont listen to music in class. B:No,I wont.好的,我不会的。(用于自己之前没做过,同时也表明自己今后也不会做时) Sorry,I wont do it in future.对不起,我今后不会这样做了。(用于自己犯错,被别人禁止做时)3)A:Lets go out for a walk.(用Lets do sth.时,常用于提出建议) B:肯定回答:Thats a good idea./That sounds good.(直接表示赞同) 否定回答:Oh,no
7、.Its too hot./Oh,no.Lets watch TV at home.(可用No作否定回答,并适当解释或提出自己的见解)祈使句一般要对方去做的动作时在将来发生。肯定回答时常用“Yes,I will.“;否定回答时常用到“No,I wont.”等。Will为“将要”之意,wont为will和not的缩写,是“将不,将不会”之意。【情态动词have to与must】【教材原句】1.We must be on time for class.2.Does he have to weat a uniform at school?3.What do you have to do?以上例句,第
8、1句含有情态动词 ,第2、3句含有情态动词 。(must,have to)【语法透析】1.have to 表示客观需要做的事情,意为“必须,不得不”。使用have to时应注意:1)have to后接动词原形,意为“必须做;不得不做”。例如:You have to wash my clothes first.你必须先洗我的衣服。2)have to有人称、数和时态的变化,其第三人称单数形式为has to,过去式为had to.例如:She has to help her mom make dinner.她不得不帮她妈妈做晚饭。3)含有have to,has to,had to的句子需分别借助助动
9、词do,does,did构成疑问句或否定句。例如:Do they have to go home now?他们得现在回家吗?You dont have to go if you dont want to.如果你不想去,你就不必去。2.must的用法:1)表示主观的义务和必要,主要用于肯定句或疑问句,意思是“必须;得;要”;由must引导的疑问句,肯定回答用must或have/has to,否定回答要用neednt或dont/doesnt have to.意为是“不必”;must的否定形式mustnt表示禁止,意思为“不能,不许”。例如:Must I finish my homework bef
10、ore six oclock?六点之前我必须完成作业吗?Yes,you must./No,you neednt./No,you dont have to.是的,你必须完成。/不,你没必要。2)表示肯定的猜测,常用于肯定句中,意为“一定是;必然”。例如:You must be very tired.你一定很累了。Mary must be in the library.玛丽一定在图书馆里。【试题链接】 I do the laundry first?No,you .You can do your homework first.A.Must;mustnt B.Can;mustnt C.Must;nee
11、dnt D.May;neednt (must 引导的一般疑问句,其否定回答用neednt或dont /doesnt have to,意为“不必”。句意:我必须先洗衣服吗?不,你不必,你可以先做作业。选C)EXERCISES:一、选择填空。( )1.The doctor says to Tom,“ stay up too late.”A.Doesnt B.Cant C.Dont D.No( )2. your homework here tomorrow,Lucy.A.Bring B.Brings C.To bring D.Bringing( )3.You dont wash all the pl
12、ates after meals.A.have to B.must C.may D.has to( )4.Bob can not come out to play because he help Dad in the garden.A.can B.can not C.has to D.must( )5.Must I clean the window now?No,you .A.mustnt B.neednt C.cant D.may not( )6. play football on the street.Its dangerous.A.Please B.Dont C.Do D.Doesnt(
13、 )7.Tom, the classroom right now.Its too dirty.A. clean B.to clean C.cleaning D.doesnt clean( )8.Dont play computer games on school nights,Li Peng! .A.Yes,I do B.Yes,I will C.Sorry,I wont D.Sorry,I dont( )9.Kate,come and help me plant trees in the garden! .A.No,I dont B.Sorry,I cant.I have to do som
14、e reading.C.Yes,but I have to go out. D.OK,I wont.( )10.Lets go shopping together,Vickers. .A.Thank you B.Youre welcome C.That sounds good D.No,you cant二、句型转换,每空一词。1.Do your homework,please.(改为否定句) 2.You cant listen to music in class. (改为祈使句) 3.No talking in the reading room.(改为同义句) 4.Dont smoke in the living room,Dad. (作出回答) 5.Dont clean the windows now. (改为肯定句) 三、将下列祈使句翻译成英语。1.请照看好您的包。 2.让我们去学校吧! 3.请小心点儿! 4.不要在教室里跑! 5.不要让狗进来! 6.禁止拍照! - 4 -