Unit 2 Home Sweet Home 单元语法：情态动词（精讲课件）-2025-2026学年八年级英语上册单元知识点精讲精练（人教版2024）

人教版初中英语语法 Unit 2 Home Sweet Home 八年级上册 人教版8年级上册（单元） 语法点 Unit 1 Happy Holiday * 不定代词 （Indefinite Pronouns） Unit 2 Home Sweet Home * 情态动词 （ Modal Verbs） Unit 3 Same or Different? * 形容词和副词比较级（Comparative Forms of Adjectives and Adverbs） Unit 4 Amazing Plants and Animals *形容词和副词最高级（Superlative Forms of Adjectives and Adverbs） Unit 5 What a Delicious Meal! * 副词的顺序和感叹句的构成和用法（the Order of Adverbs/the Structure and Usage of Exclamatory Sentences） Unit 6  Plan for Yourself * “be going to ” 结构 （“be going to” Structure） Unit 7 When Tomorrow Comes * 一般将来时will 的用法（The Usage of “Will” in the Simple Future Tense） Unit 8 Let’s Communicate! * if 引导的条件状语从句 （Conditional Adverbial Clause Introduced by “if”） 2 CONTENTS 情 态 动 词 ( Modal Verbs ) 3 情态动词是一种本身有一定词义，表示说话人的情绪、态度或语气的动词，但不能单独做谓语，只能和其 他单词原形构成谓语。 常见情态动词: can、could、may、might、must、will、would、should、shall、ought to、dare、need、have to、used to、had better 等。 4 常见情态动词 01 02 can, could may, might 03 must 04 05 will, would shall, should 06 need 07 08 dare ought to 09 had better 10 11 used to would rather 5 01 can , could 1. 表示可能性 (1)表示说话者主观猜测的可能性时， can/could常用于否定句和疑问句中。could既可以表示过去的可能性，又可以表示现在的可能性，其语气更弱一些。 He can be ill at any time. 他随时都可能会生病。 You could be right, but I don’t think you are. 你可能是对的，但我不认为你对。 We could go there this summer. 今年夏天我们可能要去那儿。 6 01 can , could 1. 表示可能性 (2) can用于肯定句中时表示理论上的可能性，即从理论上看有可能，但实际未必会发生。有时指一时的情况，常意为“有时会”。 Strikes can happen at any time. 罢工随时都可能发生。 Even an experienced climber can get into trouble. 哪怕是个有经验的登山者也可能陷入困境。 She can be very stubborn. 她有时会很固执。 7 01 can , could 1. 表示可能性 (3) can/could have done表示对过去发生的事情的推测。can have done主要用于疑问句和否定句中。 Mr. Smith can't have gone to Beijing, for I saw him in the library just now. 史密斯先生不可能去北京了，我刚才还在图书馆见过他。 Could you have mistaken Ms. Wang for her mother? 你会不会把王女士误认为是她妈妈了? Tom could have taken the money; he was here alone yesterday. 有可能是汤姆把钱拿走了，昨天他单独一个人在这里呆过。 8 02 may, might 1. 表示许可 表示请求许可时,用 may/ might均可,不过 might的语气更加委婉;在给予许可时可用 can/ may,但不能用 might。 May I use your phone? 我可以用你的电话吗？ Might I borrow your umbrella? 我可以借你的伞吗？ Might I ask a question? 我可以问个问题吗？ May I go now? Yes, you may. 我现在可以走了吗？ 可以。 9 02 may, might 2 表示可能性 may/ might表示把握性不大的推测，意为“或许；大概”。可以对现在、过去或将来的情况进行推测，常用于肯定句中。 might表示的可能性低于 may。 he may be at home. Let’s call her. 她可能在家，我们打电话吧。 It might rain tomorrow, so bring an umbrella. 明天可能会下雨，带把伞吧。 They might not agree with the plan. 他们可能不同意这个计划。 10 02 may, might 3 表示祝愿 表示祝愿时常用“ May+主语+动词原形”式倒装结构。 May you succeed! 祝你成功！ May God bless you! 愿上帝祝福你！ May you return soon! 祝你早日归来！ May you have a good journey! 祝你一路顺风！ May good luck be yours! 祝你好运！ May you be happy! 祝你快乐！ May the friendship between us last long. 祝愿我们的友情天长地久。 May you both be always happy. 祝你们俩永远幸福。 11 03 must 1. 表示必须 must表示必须，多指现在或将来的情况，强调说话者的主观语气，即说话者认为有必要或有义务做某事。一般疑问句的肯定回答用must,否定回答用needn't或者don't have to。 You must finish your homework before you watch TV. 你必须在看电视之前完成作业。 We mustn‘t waste food. 我们不能浪费食物。 —Must I finish my homework before eight o'clock?我必须在八点前完成作业吗？ —Yes, you must. 是的，你必须。 —No, you needn't. / No, you don't have to. 不，你不必。 12 03 must 2. 表示推测 must表示推测时，指有把握的、有根据的推测，只能用于肯定句。可以对现在、过去或将来的情况进行推测。对现在的情况的推测用 “must+动词原形”结构；对过去的情况进行推测-用 “must have done”结构。 It must be true. 那必定是真的。 Liars must have good memories. 说谎的人一定有好的记忆力。 He must have lived here. 他一定在这里住过。 I must have read that in some book. 我一定是在某一本书上读过这个的。 She must have been very young when she got married. 她结婚时一定很年轻。 13 03 must 3. 表示偏要、偏偏 在疑问句中must可以用来表示一个人较强烈的感情。 Must you make so much noise? I’m trying to work! 你非要弄出这么多噪音吗？我在工作呢！ Must he argue with everyone? It’s so tiring. 他非要和每个人争论吗？太让人累了。 Must you wear that ugly shirt today? We’re going to a party! 你今天非要穿那件难看的衬衫吗？我们可是要去参加派对的！ Must she always interrupt when I’m speaking? 她为什么偏偏总要在我说话时插嘴？ 14 04 will, would (1) 表示自愿做或主动提出做某事，如意志、愿望或决心等，可用于各种人称。would是will的过去式。 We will organize the party if you’re busy. 如果你忙的话，我们来组织派对。 They will never give up their dreams. 他们绝不会放弃自己的梦想。When I was a child, my father would read me stories every night. 我小时候，爸爸每晚都会给我读故事。 They would never admit their mistakes when they were young. 他们年轻时从不愿承认错误。 15 04 will, would (2) 表示征求意见或提出请求，多用于第二人称作主语的疑问句中，would不表示过去式，而表示语气比较委婉。 Will you pass me the salt? 你能把盐递给我吗？ Will you let me know your decision by Friday? 你能在周五前告诉我你的决定吗？ Would you mind helping me with this suitcase? 你介意帮我拿一下这个行李箱吗？ Would you like to go for a walk after dinner? 晚饭后你想去散步吗？ 16 04 will, would (3) 带有主观性，意为“总是”。will表示现在的习惯， would表示过去的习惯。 My little sister will sing that song over and over again when she’s happy. 我妹妹高兴的时候，总是反复唱那首歌。 The old man will sit in the park for hours every afternoon, watching the children play. 那位老人每天下午总是在公园里坐几个小时，看孩子们玩耍。 She would always bring homemade cookies to class when she was in high school. 她高中时，总是带自制饼干到班里来。 17 05 shall, should shall 主要用于第一人称（I/we），表达征求意见、提出建议或承诺，语气较正式。 1. 用于第一人称（I/we）的疑问句，征求对方意见（“…… 好吗？”“要不要……？”） Shall we go to the park this weekend? 这周末我们去公园好吗？ Shall I help you carry the bag? 我帮你拿包好吗？ 2. 用于第一人称（I/we）的陈述句，表承诺、决心或安排（多用于正式场合） I shall finish my homework before dinner. 我会在晚饭前完成作业。 We shall meet at the school gate at 8:00. 我们 8 点在校门口集合。 18 05 shall, should should 是 shall 的过去式，但在初中阶段，它更常用作独立情态动词，表 “应该”“建议” 或 “推测”。 1. 表示 “应该”（强调责任、义务或合理建议） We should study hard for the exam. 我们应该为考试努力学习。 2. 用于第一人称疑问句，征求对方的建议（“我 / 我们应该…… 吗？”） Should we start the meeting now? 我们现在应该开始开会吗？ 3. 表示推测（“按理说应该”，可能性较大） The train should arrive at 9:00. 火车按理说 9 点到。 She should be at home now. 她现在应该在家。 19 06 need need作情态动词时多用于否定句和疑问句中，无人称和数的变化，后接动词原形。由need引起的一般疑问句，肯定回答常用must或have to,否定回答常用needn't。need做情态动词时通常用在疑问句、否定句中，或与条件句whether, hardly, nobody等连用。 Need I finish the work today? 我需要今天完成这项工作吗？ → Yes, you have to. / No, you needn‘t. 是的，必须今天完成。/ 不，不必今天完成。 She needn‘t come to the meeting if she is busy. 如果她忙，就不必来参加会议。 Nobody need tell him the truth. 没人需要告诉他真相。 Needn‘t you pay the bill today? 你今天不用付账单吗？ 20 dare 07 (1) 情态动词 dare 主要用于否定句、疑问句或条件句中， 后接动词原形； 否定形式直接加 “not”（缩写为 daren't）。 否定句：表示 “不敢” She daren‘t speak in front of the class. 她不敢在全班面前说话。 疑问句：表示 “敢吗？” Dare you swim across the river? 你敢游过这条河吗？ 与 if 等引导的条件句连用 If you dare (to) cheat in the exam, you’ll be punished. 如果你敢考试作弊，会受惩罚的。 21 dare 07 (2) dare 作实义动词 实义动词 dare 可用于各种句式, 后接带 “to” 的不定式（即 dare to do sth.）；否定句和疑问句需借助助动词（do/does/did）。 肯定句：表示 “敢于做某事” She dares to sing in public. 她敢于在公共场合唱歌。 否定句：表示 “不敢做某事” They don’t dare to climb that high mountain. 他们不敢爬那座高山。 疑问句：表示 “敢做某事吗？” Do you dare to jump over the fence? 你敢跳过栅栏吗？ Did she dare to argue with her father? 她敢和父亲争论吗？ 22 08 ought to ought to表示应该，比should的语气略强, should多表达自己的主观看法， ought to多反映客观情况。在谈到法律义务和规定时，常用ought to。其否定式是在to之前加not，疑问式是把ought提至主语前。 You ought to start at once. 你应该马上开始。 The children ought not to play so close to the road. 孩子们不应该在靠马路这么近的地方玩耍。 You ought not to smoke in public places. 你不应该在公共场所吸烟。 23 09 had better had better 表示现在或未来的动作，是说话者认为某人在某个特定的情况下应该做某事，后面接不带 to 的不定式，其中的 had 不是 have 的过去式。 基本结构 肯定形式：had better + 动词原形（即 had better do sth.） （ “had” 没有人称和数的变化，无论主语是第几人称，都用 “had”，不能用 “has” 或 “have”。） 否定形式：had better + not + 动词原形（即 had better not do sth.） 缩写形式：主语 + 'd better ...（“had” 常与主语缩写，如 I'd, you'd, he'd 等） 24 09 had better 表示建议或劝告（“最好做某事”） You had better take an umbrella. It’s going to rain. 你最好带把伞，要下雨了。He had better study hard for the exam. 他最好为考试努力学习。 2. 否定形式：表示 “最好不要做某事” You had better not be late for class. 你最好不要上课迟到。 He had better not eat too much junk food. It’s bad for his health. 他最好不要吃太多垃圾食品，对健康不好。 3. 疑问句：用于征求对方意见（“最好…… 吗？”） 结构：Had + 主语 + better + 动词原形？ Had I better finish the work first? 我最好先完成工作吗？ 25 10 used to used to的意思是“过去经常”，其中的to是不定式符号，不是介词，所以其后接动词原形。used to与often, always, never等副词连用时，通常置于副词之后，也可置于副词之前。 I used to play basketball after school. 我过去常常放学后打篮球。 They didn’t use to travel by plane. 他们过去不常坐飞机旅行。 Did he use to play the piano? 他过去常常弹钢琴吗？ I didn’t use to like vegetables. 我过去不喜欢吃蔬菜。 She used to have short hair.她过去留短发。 26 11 would rather 1. 表示 “宁愿做某事”（自身选择） 结构：主语 + would rather + 动词原形 （would 常缩写为 ‘d，无人称变化，无论主语是第几人称，都用 would rather） I would rather stay at home than go out. 我宁愿待在家里也不愿出去。 She ‘d rather read books in the library. 她宁愿在图书馆看书。 They would rather walk to school. 他们宁愿步行上学。 They ‘d rather start the project tomorrow. 他们宁愿明天开始这个项目。You would rather watch cartoons, right? 你宁愿看动画片，对吗？ 27 11 would rather 2. 表示 “宁愿做 A 而不愿做 B”（两者对比） 结构：主语 + would rather + 动词原形 + than + 动词原形 （than 后接动词原形，前后动词形式保持一致） He would rather play football than play basketball. 他宁愿踢足球也不愿打篮球。 We 'd rather watch a movie than listen to music. 我们宁愿看电影也不愿听音乐。 You would rather eat rice than eat noodles, right? 你宁愿吃米饭也不愿吃面条，对吗？ 28 practice 1．You’ve dialed the wrong number. The number of our school ________ be 5551234. A．can B．may C．need D．ought to 2．You’d better not ________ too much TV. It’s bad for your eyes. A．watch B．to watch C．watching D．watched 3．My little brother is afraid of dogs. He ______ go near them. A．dare not B．dares not C．dare D．dares 4．—Would you come to my birthday party tomorrow evening? —I’m afraid I ______. I have to look after my grandparents. A．wouldn’t B．can’t C．won’t 5．—It’s getting cold. ________ I turn on the heating? —No, thanks. A．Must B．Need C．Shall D．Will D A A B C 29 practice 6．We ________ eat in the classroom. A．can’t B．must C．have to 7．________ we to do the survey right now? Can we do it later? A．Need B．Ought C．Must D．Should 8．You ________ to wear the school uniform at school. It’s the school rule. A．ought B．can C．may D．need 9．Students ________ to be careful when they do chemical experiments in the lab. A．should B．must C．ought D．may 10．We ________ keep our classroom clean because it is our duty. A．can B．may C．ought to D．need A B A C C 30 practice 11．—How is the weather today? —It’s hot. You ________ wear the coat. A．needn’t B．shouldn’t C．must D．can’t 12．—_______ you like to go shopping with me? —Yes, I’d love to. A．Need B．May C．Would D．Can 13．Don’t talk to the old like that, Jack. We ________ be patient with them and show our love and kindness to them. A．can B．may C．should D．would 14．I ______ like a cup of tea, please. A．will B．should C．would D．could 15．—Don’t use my computer, please. —Sorry, I ________ use it again. A．won’t B．can’t C．don’t A C C A C 31 practice 16．—Are you going to Nancy’s birthday party this afternoon? —It depends. I ________ have to cook dinner for my grandparents. A．might B．should C．must D．can’t 17．—Kevin, where is the book The Daydreamer? —I’m not sure. It _______ be on the coffee table in the living room. A．must B．might C．will 18．—Kimmy, never throw any object from the building. —OK. I know even a small object ________ cause serious injuries or death when dropped from a great height. A．should B．must C．may D．need A B C 32 practice 19．Tina isn’t as shy as she ________. She ________ to sing in front of crowds. A．is, dares B．used, dare C．are used to be, dare D．used to be, dares 20．I ________ not speak English in public when I was in England for a holiday. A．should B．must C．dared 21．The girl is so shy that she ________ speak in public. A．dare not B．dares not C．not dare D．not dares 22．Jane used to be silent and ______ with strangers, but she can give a speech in public now. A．didn’t dare to talk B．dared not to talk C．didn’t dare talk 23．All the children knew who broke the window, but they________ point out. A．daren’t B．daren’t to C．dare D．dare to D C A A A 33 practice 24．Only an arm’s length away, but he still ________ reach the crayfish. A．shouldn’t B．mustn’t C．wouldn’t D．couldn’t 25．—Would you like ________ tea with ice in it? —Yes, I ________ . A．any, would B．some, would C．any, will D．some, will 26．—Whose English book is this? —It________ be Lily’s, but I’m not sure. A．will B．might C．must D．need 27．—Don’t play the dangerous game. —Sorry! I ________ do it. A．won’t B．don’t C．can’t D．mustn’t 28．—Didn’t you see the zebra crossing? You _________ slow down! —Sorry, sir. Am I going to fail the driving test? A．may B．can C．must D．will D B B A C 34 THE END 35 $$