Unit2语法专项课件—情态动词与不定代词专项课件-2025-2026学年北师大英语八年级上册

教学课件 北师大英语八年级上册 Unit2 语法专项 情态动词（must/mustn’t, have to/don’t have to, should/shouldn’t）与不定代词 全解精讲+分层练习 1 学习目标 掌握must/have to/should三类情态动词的核心用法与语气差异 能正确使用情态动词的否定形式，区分主观与客观要求 掌握指人/指物不定代词的用法，熟记句式搭配规则 学会用形容词修饰不定代词，掌握主谓一致原则 运用所学完成单选、填空、句型转换等多种题型 情态动词 核心特征 情态动词本身有词义，表语气、态度或情态，无人称变化 后接动词原形，不能单独作谓语，需和实义动词构成谓语 否定形式直接在其后加not，部分有固定缩写（mustn’t/shouldn’t） 本单元重点掌握must/have to/should三组情态动词及否定式 must / mustn’t 核心用法 must表必须、义务，强调主观要求或规定，语气强烈 结构：must + 动词原形，无人称和数的变化 mustn’t表禁止、不准，是最强否定，表绝对不允许 例句：You must obey the school rules. You mustn’t fight with others. have to / don’t have to 核心用法 have to表不得不、必须，强调客观需要，由外界规则/环境决定 结构：have to + 动词原形，有人称变化（has to/had to） don’t have to表不必，语气委婉，表没有客观要求做某事 例句：She has to get up early for school. You don’t have to finish it today. should / shouldn’t 核心用法 should表应该、应当，用于提建议、劝告，语气比must委婉 shouldn’t表不应该，用于劝阻，语气温和，无强制意味 结构：should/shouldn’t + 动词原形，无人称变化 例句：You should wash your hands often. You shouldn’t waste food. 三类情态动词用法对比表 情态动词 核心含义 语气强度 核心考点 must/mustn’t 必须/禁止 强/最强 主观要求、绝对禁止 have to/don’t have to 不得不/不必 中/弱 客观需要、有人称变化 should/shouldn’t 应该/不应该 中/中 建议劝告、语气委婉 must与have to 易混辨析 must表主观意愿，说话人自己要求做某事，无时态变化 have to表客观被迫，外界因素要求做某事，有过去式had to 两者肯定式可互换，否定式不可：mustn’t(禁止)≠don’t have to(不必) 例句：I must study hard.（自己想） I have to study hard.（家长要求） 情态动词 特殊用法拓展 must除表“必须”，还可表肯定推测，意为“一定” 例句：The light is on. He must be at home. have to的将来式：will have to，表将来的客观要求 例句：We will have to take a test tomorrow. 不定代词 核心定义 不定代词是指代不确定的人、事物或数量的代词 不具体指明代替的对象，可指人、可指物 在句中可作主语、宾语、表语，用法有固定规则 本单元重点掌握8个高频不定代词：指人4个+指物4个 指人不定代词 用法 指人不定代词：someone/anyone/no one/everyone someone（某人）：用于肯定句，表不确定的人 anyone（任何人）：用于否定句/疑问句/条件句 no one（没有人）：表否定，可单独作主语 everyone（每个人）：用于肯定句，表全体 指物不定代词 用法 指物不定代词：something/anything/nothing/everything something（某事/物）：用于肯定句，表不确定的事物 anything（任何事/物）：用于否定句/疑问句/条件句 nothing（没有什么）：表否定，可单独作主语 everything（一切）：用于肯定句，表所有事物 不定代词 核心用法要点1 主谓一致：所有不定代词作主语时，谓语动词用单数形式 这是高频考点，无论指人还是指物，均遵循此规则 例句：Someone is calling you. Everything is ready. No one knows the answer. Everyone likes music. 不定代词 核心用法要点2 形容词后置：形容词修饰不定代词时，要放在不定代词后面 结构：不定代词 + 形容词，不可将形容词放在前面 例句：something interesting（有趣的事）， nothing important（无关紧要的事） anyone clever（聪明的人），everything new（所有新事物） 不定代词 句式搭配拓展 something/anyone等可用于表示请求、建议的疑问句中 表委婉语气，此时不用考虑“疑问句用any”的规则 例句：Would you like something to drink? Can someone help me? nothing与not anything 同义转换 nothing本身表否定，意为“没有什么”，可与not anything互换 结构：nothing = not + anything，改写句子时可灵活替换 例句：There is nothing in the bag. = There isn’t anything in the bag. I see nothing. = I don’t see anything. 语法小练 单项选择 1.You ______ touch the wet wire. It’s very dangerous. A. must B. mustn’t C. have to D. don’t have to 2.I ______ go to the doctor. I have a bad cold. A. must B. should C. have to D. shouldn’t 3.You ______ take an umbrella. It’s not going to rain. A. mustn’t B. don’t have to C. shouldn’t D. can’t 4.______ is waiting for you at the school gate. A. Someone B. Anyone C. No one D. Everyone B C B A 5.You ______ read more books. It’s good for your study. A. must B. have to C. should D. can’t 6.There is ______ wrong with my phone. It doesn’t work. A. something B. anything C. nothing D. everything 7.Did you find ______ in the classroom after school? A. someone B. anyone C. no one D. everyone 8.You ______ eat too much sugar. It’s bad for your teeth. A. mustn’t B. don’t have to C. shouldn’t D. can’t C A B C 9.______ likes the new teacher. She is kind and helpful. A. Someone B. Anyone C. No one D. Everyone 10.I didn’t buy ______ for my parents on my trip. A. something B. anything C. nothing D. everything 11.He ______ get up early because he lives far from school. A. must B. has to C. should D. can 12.There is ______ in the fridge. Let’s go shopping. A. something B. anything C. nothing D. everything D B B C 13.You ______ follow the traffic rules when you cross the road. A. must B. should C. have to D. A and C 14.Is there ______ interesting in today’s newspaper? A. something B. anything C. nothing D. everything 15.You ______ worry about him. He can take care of himself. A. mustn’t B. don’t have to C. shouldn’t D. can’t D B B 语法小练 用所给词适当形式填空 1.You must _________ (obey) the traffic rules when you drive. 2.She has to _________ (finish) her work before 5 o’clock. 3.There is something ____________ (important) to tell you. 4.You should _________ (drink) more water every day. 5.Did you see _________ (someone) near the park? obey finish important drink anyone 语法小练 用所给词适当形式填空 6.You mustn’t _________ (smoke) in the public place. 7.Everyone _________ (like) the beautiful scenery here. 8.You don’t have to _________ (come) to the office on weekends. 9.There is nothing __________ (difficult) in the exercise. 10.You shouldn’t __________ (spend) too much time on games. smoke likes come difficult spend 语法小练 句型转换 1.You must clean your room every day.（改为否定句） You __________ __________ your room every day. 2.He has to go to school by bus.（改为一般疑问句） ______ he ______ ______ go to school by bus? 3.There is something new in the magazine.（改为否定句） There is ______ ______ in the magazine. needn’t clean Does have to nothing new 语法小练 句型转换 4.You should go to bed early.（改为否定句） You ___________ ___________ to bed early. 5.I have to stay at home because I’m ill.（对划线部分提问） ______ ______ you ______ to stay at home? 6.Everyone likes this movie.（改为否定句） ______ ______ likes this movie. shouldn’t go Why do have No one 7.You mustn’t swim in this river.（改为同义句） You ___________ __________ _________ _______ swim in this river. 8.There is nothing in the box.（改为同义句） There ____________ ___________ in the box. 9.She has to finish the work today.（改为否定句） She _________ _________ _________ finish the work today. 10.Someone is knocking at the door.（改为一般疑问句） __________ __________ knocking at the door? are not allowed to isn’t anything doesn’t have to Is anyone 语法小练 根据汉语完成句子 1.你必须按时完成你的作业。 You ______ ______ your homework on time. 2.你不必今天去超市。明天去也可以。 You ______ ______ ______ go to the supermarket today. 3.桌子上有一些好吃的东西。 There is _________ _________ on the table. 4.你应该多做运动来保持健康。 You ______ ______ more exercise to keep healthy. 5.没有人知道这个问题的答案。 ______ ______ ________the answer to this question. must finish don’t have to something delicious should do No one knows 语法拓展 情态动词的回答 must引导的一般疑问句，肯定回答用must，否定回答用needn’t 例句：—Must I go now? —Yes, you must. / No, you needn’t. should引导的疑问句，回答用should/shouldn’t，或I think you should 高频易错点 混淆must和have to的语气，客观要求用must，主观要求用have to 情态动词后接动词ing形式，如must going，正确应为must go 不定代词作主语时，谓语动词用复数，如 Everyone like 形容词修饰不定代词时前置，如interesting something，正确应为something interesting 否定句中用something，如I don’t have something，正确应为anything mustn’t与don’t have to混用，表“不必”用mustn’t 语法辨析 不定代词some/any系列用法 some系列（someone/something）：主要用于肯定句、委婉请求句 any系列（anyone/anything）：主要用于否定句、一般疑问句 no系列（no one/nothing）：直接表否定，无需再加not everything/everyone：表全体，用于肯定句，谓语用单数 单元核心 知识总结 情态动词must/have to/should表不同语气，must主观、have to客观、should表建议 情态动词后接动词原形，否定式有固定搭配，mustn’t表禁止，don’t have to表不必 不定代词分指人/指物，遵循“形容词后置、主谓单数”原则 some系列用肯定句，any系列用否定/疑问句，nothing=not anything 教学课件 Unit2 语法专项 情态动词（must/mustn’t, have to/don’t have to, should/shouldn’t）与不定代词 Thank you for listening! 31 $