内容正文:
译林版(新教材)八年级上册Unit 4 Hands-on fun语法讲练
祈使句 & should / had better
核心语法1:祈使句
知识点1 核心语法讲解
祈使句是专门用来向对方发出指令的句子,省略主语 you(你/你们),谓语统一使用动词原形;主要用于表达请求、命令、劝告、警示,以及公共禁令标语。
句式分类
基础结构
例句+解析
Do型
祈使句
动词原形+宾语/其他
① Please have a seat here.
翻译:请这边坐。
② This way, please. = Go this way, please.
翻译:请这边走。(省略动词特例)
③ Do wait for me after class!
翻译:下课后一定要等我!(Do加强语气)
Be型
祈使句
Be + 名词/形容词(表语)
Be a good boy!
翻译:做一个听话的好孩子!
Let型
祈使句
Let + 人称宾格 + 动词原形
1. Let’s do sth.(包含听话人,共同做某事)
例:Let’s make a model car. 咱们一起做模型车吧。
2. Let us do sth.(不包含听话人,请求对方许可)
例:Let us finish homework first. 让我们先写完作业。
No禁令型
祈使句
No + 动名词(doing)
No smoking! / No fishing! / No parking!
翻译:禁止吸烟/禁止垂钓/禁止停车
转换公式:No doing = Don’t + 动词原形
例:No smoking = Don’t smoke.
知识点2 祈使句的否定形式(必考易错点)
1. Do 型、Be 型祈使句否定:
变化规则:直接在句子开头加助动词 “Don’t”,后面动词仍保持原形。
例句1:Don’t forget me! 不要忘记我。
例句2:Don’t be late for school! 上学不要迟到。
2. Let类祈使句否定:
① Let + 人称宾格/人名
请求对方允许某人做某事,不包含听话人在内。
否定结构:Don’t let + 宾格 + 动词原形
例句:Don’t let him cross the busy road alone. 别让他独自横穿车流大的马路。
② Let’s(Let us的缩写形式)
向听话人发出共同提议,所有人一起做某事,包含听话人。
否定结构:Let’s not + 动词原形
例句:Let’s not make any noise. 咱们不要吵闹。
知识点3 拓展句型:祈使句 + and / or + 一般将来时
可等价改写为if引导的条件状语从句
搭配结构
逻辑关系
例句+从句转换解析
祈使句 + and + 将来句
顺承关系,做到就会有好结果
Work hard, and you will get good grades.
= If you work hard, you will get good grades.
翻译:努力学习,你就能取得好成绩。
祈使句 + or + 将来句
转折警示,不做就会产生坏结果
Hurry up, or we will miss the train.
= If we don’t hurry up, we will miss the train.
翻译:快点,否则我们赶不上火车。
知识点4 重难点拓展:祈使句反意疑问句(单元必考)
句子开头类型
固定反疑问尾句
例句解析
普通Do/Be/Don’t祈使句
will you
Be quiet, will you?
翻译:安静点,好吗?
Let’s 开头祈使句
shall we(包含听话人,共同提议)
Let’s go hiking, shall we?
翻译:我们去远足,好吗?
Let us 开头祈使句
will you(请求对方许可,不含听话人)
Let us play outside, will you?
翻译:让我们出去玩,行吗?
核心语法2:should / had better(提建议句型)
知识点1 核心语法讲解
should 意为“应该”,后必须接动词原形,用于温和劝告、合理建议、阐述责任义务。
句式类型
标准结构
例句+翻译解析
肯定句
主语 + should + 动词原形
We should protect the environment.
翻译:我们应该保护环境。
否定句
主语 + shouldn’t (should not) + 动词原形
You shouldn’t cut in line.
翻译:你不应该插队。
一般疑问句
Should + 主语 + 动词原形?
— Should we help old people cross the road?
我们应该扶老人过马路吗?
— Yes, we should. / No, we shouldn’t.
had better(缩写 ’d better)整体视作情态短语,后只接动词原形,语气带有警告意味。
句式
类型
标准结构
易错点+例句解析
肯定句
had better do sth.
最好做某事
易错点:无论主语是谁,永远用had better,无have better/has better
You’d better get some sleep.(你最好睡一会儿。)
否定句
had better not do sth.
最好不要做某事
易错点:not放在better与动词原形中间,不加to
You’d better not waste any more of your time.(你最好不要再浪费时间了。)
知识点2 对比辨析:should VS had better
短语
语气强弱
适用场景
配套例句解析
should
温和、客观
通用日常建议、道德义务、生活习惯
You should wash your hands before meals.
翻译:你饭前应该洗手。(常规合理建议)
had better
强烈、带警示
提醒规避危险、避免损失、及时补救
You’d better take an umbrella. It’s going to rain.
翻译:你最好带上雨伞,马上要下雨了。(不做会淋雨,带有警告)
考点精练
一、单项选择(共25小题)
从A、B、C、D四个选项中,选出可以填入空白处的最佳选项。
( )1.To save elephants, let’s ________ anything made of ivory.
A.buy B.not buy C.buying D.not buying
( )2.Don’t be crazy about short videos, __________________ you will lose the ability to think deeply.
A.and B.or C.but D.so
( )3.________ your heart open, ________ you will experience the happiness that friendship brings you.
A.Keeping; so B.Keep; so C.Keeping; and D.Keep; and
( )4.________ afraid of making mistakes. You can learn from them.
A.Be B.Be not C.Not to be D.Don’t be
( )5.Jack, slow down. ________ run in the hallways. It’s not safe.
A.No B.Not C.Don’t D.Doesn’t
( )6.“Please ________ quiet” means “Please ________ make noise”.
A.is; not B.being; no C.be; doesn’t D.be; don’t
( )7.Let me ________ you how ________ this camera.
A.show; to use B.to show; use C.showing; using D.show; using
( )8.—________ a break if you are tired, Jack.
—Thank you, mum. I will.
A.Takes B.To take C.Take D.Took
( )9.________ sure that there are no mistakes in your paper, or you cannot get A.
A.Make B.To make C.Making D.Makes
( )10.Look at the sign. No ________! You can’t smoke here.
A.smoke B.smokes C.smoking D.smoked
( )11.— Please be quiet in the library! Look at the sign. It says, “No _______”.
— I am sorry.
A.talk B.talking C.read D.reading
( )12.________ your brother ________ computer games all day. It’s bad for his eyes.
A.Don’t let; play B.Let; play C.Let’s; not play D.Let; don’t play
( )13.Rome wasn’t built in one day. ________ patient, or you can’t finish the task in such a short time.
A.Be B.To be C.Being D.Been
( )14.Let Jane _________ the art club. She likes drawing very much.
A.joins B.joining C.to join D.join
( )15.Let’s _________ some ________ and carrots.
A.buy; potatoes B.buy; potato C.to buy; potatoes D.buying; potatoes
( )16.If you want to get along with your classmates, you ________ shout at them.
A.needn’t B.can’t C.may not D.shouldn’t
( )17.You had better ________ wine because you have to drive home.
A.not drink B.don’t drink C.not to drink D.not to drinking
( )18.You ________ stay up late. It’s bad for your eyes and health.
A.must B.should C.shouldn’t D.mustn’t
( )19.If you have a backache, you ________lift heavy things. You ________ lie down for a good rest.
A.had better; shouldn’t B.shouldn’t; had better not
C.shouldn’t; had better D.had better not; mustn’t
( )20.— I feel like I’m infected with COVID-19.
—Don’t worry. You ________ sleep more and ________ sweet food like canned yellow peaches.
A.shouldn’t: had better not to eat B.should; had better not to eat
C.shouldn’t: had better not eat D.should; had better not eat
( )21.The instructions are very important, you ________ begin your work without reading them.
A.needn’t B.couldn’t C.shouldn’t D.mustn’t
( )22.—________ I go out to play basketball now, Mom?
—No, you can’t. You ________ go to finish your homework first.
A.Must; should B.Must; can C.Could; should D.Could; can
( )23.You’d better ________ on your parents too much. You should be independent.
A.depend B.not to depend C.don’t depend D.not depend
( )24.—Mum, the fruit salad on the table looks delicious! Can I taste it?
—Sure, but you’d better ________ your hands first.
A.to wash B.not to wash C.wash D.not wash
( )25.You'd better _________ early, or you will miss the first class.
A.not get up B.get up C.to get up D.getting up
二、句型转换(共15小题)
按要求完成下列句子,每空一词。
1.Let’s make fruit salad. (改为否定句)
________ ________ ________ fruit salad.
2.Stop playing in the street. It’s dangerous. (改为同义句)
_________ _________ in the street. It’s dangerous.
3.If you work hard, you will succeed.(改为同义句)
________ hard, ________ you will succeed.
4.If you don’t take the chance, you will regret it.(改为同义句)
________ the chance, ________ you will regret it.
5.Be silent. (改为否定句)
________ ________ silent.
6.Add some sugar to the coffee please.(改为否定句)
________ ________ ________ sugar to the coffee, please.
7.You can’t touch the desk because the paint is wet. (改为同义句)
________ ________ the desk because the paint is wet.
8.Remember to buy a gift for your cousin.(改为同义句)
________ ________ ________ ________ a gift for your cousin.
9.You have to drive on.Look at the sign! It says “Don't Park”.(改为同义句)
You have to drive on.Look at the sign! It says “_________ ________”.
10.If you are late, the teacher will be angry. (改为同义句)
________ ________ late, ________ the teacher will be angry.
11.You’d better practise playing the guitar at night. (改为否定句)
You ________ ________ ________ practise playing the guitar at night.
12.You should lie down and rest. (改为否定句)
You ________ ________ down and rest.
13.It’s best for you to read the textbook aloud.(改为同义句)
You ________ ________ read the textbook aloud.
14.Saline should eat some vegetables more often. (改为一般疑问句)
________ Saline eat ________ vegetables more often?
15.Taking this medicine three times a day is necessary for you. (改为同义句)
You ________ ________ this medicine three times a day.
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答案解析
一、单项选择
1. 答案:B。解析:Let’s 后接动词原形,否定结构为 Let’s not do sth.,句意为“为保护大象,我们不要购买任何象牙制品”;A buy 肯定含义不符合语境,C buying、D not buying 形式错误,let’s 后不能加doing。
2. 答案:B。解析:祈使句 + or + 将来时,or 表示“否则”,表不做前半句动作会产生坏结果;句意为“不要沉迷短视频,否则你会失去深度思考的能力”;and 表顺承,but 但是,so 因此,逻辑均不符。
3. 答案:D。解析:前半句为Do型祈使句,用动词原形Keep开头;祈使句+and+将来时,and表顺承,做到前半句就会有好结果;句意为“敞开心扉,你就能体会友谊带来的快乐”;Keeping是非谓语,so不能搭配该句型。
4. 答案:D。解析:Be型祈使句否定式为Don’t be + 形容词;句意为“不要害怕犯错,你能从错误中学习”;A Be是肯定祈使句,B Be not结构不标准,C Not to be不能单独开头构成祈使句。
5. 答案:C。解析:Do型祈使句否定直接开头加Don’t,后接动词原形run;No后接动名词,Not不能单独引导祈使句否定,Doesn’t主语为三单,祈使句无主语。
6. 答案:D。解析:第一空Be型祈使句用原形be;第二空Do型否定祈使句用don’t + 动词原形make;is/being形式错误,doesn’t主语为三单,不符合祈使句规则。
7. 答案:A。解析:固定搭配let sb. do sth.,let后宾格搭配动词原形show;how to do sth. 是“疑问词+不定式”固定结构,作宾语;to show、showing、using均不符合搭配规则。
8. 答案:C。解析:本句为Do型祈使句,直接用动词原形Take开头表劝告;Takes三单、To take不定式、Took过去式均不能独立引导祈使句。
9. 答案:A。解析:祈使句以动词原形Make开头,固定搭配make sure确保;To make、Making是非谓语,Makes三单,无法构成指令类祈使句。
10. 答案:C。解析:No型禁令祈使句结构为No + 动名词doing,smoking是smoke的动名词;smoke原形、smokes三单、smoked过去式均不能跟在No后。
11. 答案:B。解析:标识标语No后接动名词,图书馆禁止交谈,No talking禁止喧哗;talk原形、read/reading语义不符。
12. 答案:A。解析:Don’t let sb. do sth. 不让某人做某事;句意为“别让你弟弟整天玩电脑游戏,伤眼睛”;Let肯定含义不符,Let’s包含说话人,此处主语是your brother,don’t let结构唯一正确。
13. 答案:A。解析:Be型祈使句用原形Be开头;祈使句+or结构,句意为“要有耐心,不然你没法短时间完成任务”;To be、Being非谓语,Been过去分词均不能引导祈使句。
14. 答案:D。解析:固定搭配let sb. do sth.,let后必须加动词原形join;joins三单、joining动名词、to join不定式均不符合搭配。
15. 答案:A。解析:Let’s后接动词原形buy;potato复数变形为potatoes,some后接可数名词复数;to buy、buying形式错,potato单数不能跟some搭配。
16. 答案:D。解析:shouldn’t 不应该,用于提出劝告,句意为“如果你想和同学好好相处,不应该冲他们大喊”;needn’t不必,can’t不能(客观禁止),may not可能不,语气和场景不符。
17. 答案:A。解析:had better否定结构为had better not do sth.,中间不加to;句意为“你最好别喝酒,你还要开车回家”;don’t drink、not to drink、not to drinking均违背搭配规则。
18. 答案:C。解析:shouldn’t不应该,温和劝告不要熬夜;must必须,should应该为肯定含义;mustn’t表示“严禁(有明文规定)”,此处只是健康劝告,不用mustn’t。
19. 答案:C。解析:第一空shouldn’t lift 不应该搬重物(劝告);第二空had better lie down最好躺下休息;句意为“如果你背痛,不该提重物,最好躺下好好休息”,其余选项逻辑相反。
20. 答案:D。解析:第一空should 应该,建议多睡觉;第二空had better not do sth.,not后直接加动词原形eat,无to;句意为“你应该多睡觉,最好别吃甜食”,A/C shouldn’t语义相反,B多了to结构错误。
21. 答案:C。解析:shouldn’t不应该,劝告不要不看说明就开工;needn’t不必,couldn’t不能(过去能力),mustn’t严禁(强制规定),此处是合理建议,用shouldn’t。
22. 答案:C。解析:第一空Could I... 委婉请求许可;第二空should应该,给出建议先完成作业;Must我必须?语义不通,can不能用于提建议。
23. 答案:D。解析:had better not do sth.,否定直接在better后加not,接动词原形depend;not to depend、don’t depend、to depend均不符合固定搭配。
24. 答案:C。解析:had better后接动词原形wash;句意为“你最好先洗手再吃沙拉”;not wash是否定,和语境“当然可以尝”矛盾,带to的形式均错误。
25. 答案:B。解析:祈使句or表否则,句意为“你最好早起,否则会错过第一节课”;not get up语义相反,to get up、getting up形式不符合had better do规则。
二、句型转换
1. 答案:Let’s not make。解析:Let’s引导的祈使句变否定,固定结构Let’s not + 动词原形,make不变。
2. 答案:Don’t play。解析:原句Stop playing = Don’t play,Do型祈使句否定,don’t后接动词原形。
3. 答案:Work;and。解析:if条件句(肯定顺承)转换为“祈使句 + and + 将来时”,动词原形Work开头,and表顺承。
4. 答案:Take;or。解析:if you don’t…(不做就有坏结果)转换为“祈使句 + or + 将来时”,动词原形Take开头,or表否则。
5. 答案:Don’t be。解析:Be型祈使句变否定,句首加Don’t,后接be动词原形。
6. 答案:Don’t add any。解析:Do型祈使句否定开头Don’t + 动词原形add;some在否定句中改为any。
7. 答案:Don’t touch。解析:You can’t touch 同义替换为否定祈使句Don’t touch,表禁止触碰。
8. 答案:Don’t forget to buy。解析:remember to do sth.记得做 = don’t forget to do sth.不要忘记做,否定祈使句结构。
9. 答案:No Parking。解析:Don’t Park(禁止停车)等价于No + 动名词,park动名词为parking,公共标识固定写法。
10. 答案:Don’t be;or。解析:if you are late(不按时会有坏结果)转换为否定祈使句Don’t be late,后接or表否则。
11. 答案:had better not。解析:had better变否定,直接在better后加not,完整结构You had better not do。
12. 答案:shouldn’t lie。解析:should变否定直接加not,缩写shouldn’t,后接动词原形lie。
13. 答案:had better。解析:It’s best for sb. to do = sb. had better do,同义转换,had better后接动词原形。
14. 答案:Should;any。解析:含should陈述句变一般疑问句,should提前;some在疑问句改为any。
15. 答案:should take。解析:It’s necessary for you to do(你有必要做)同义替换为you should do,should后接动词原形take。
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