Unit 3 What makes a great team语法精讲精练2025-2026学年外研版英语八年级下册

该初中英语知识清单聚焦外研版八下Unit3情态动词语法，系统梳理should、must、can、need、had better五大核心情态动词，先阐述情态动词共同特征，再分点讲解各词含义、肯否句式及易混点，搭建从基础特征到具体应用的递进式学习支架。 清单通过对比表格（如must与have to辨析）、五大情态动词速查总表整合知识体系，分层设计单选、填空、句型转换练习，典型例题精讲易错点，培养学生语言能力和思维品质。答案解析详尽，辅助教师精准教学，助力学生自主突破语法难点，提升学习效率。

外研版八下 Unit 3 What makes a great team?语法精讲精练 —— 情态动词（一）should / must / can / need / had better —— 使用说明 情态动词表示说话人对有关行为或事物的态度和看法，如命令、允诺、义务、可能、需要等，是初中英语的重点和中考高频考点。本讲为情态动词第一课时（同步入门版），先讲情态动词的共同特征，再系统梳理 should、must、can、need、had better 五个最常用情态动词的含义、肯否句式与易混点，配套三类分层练习，答案与解析统一附于文末。 第一讲 知识精讲 一、情态动词的共同特征 ① 情态动词本身有一定词义，但不能单独作谓语，必须和后面的动词原形一起构成谓语；② 一般没有人称和数的变化（have to、be able to 除外）；③ 后接动词原形；④ 否定形式直接在情态动词后加 not；⑤ 疑问句把情态动词提到主语前。 特征 说明 例句 后接动词原形 情态动词 + do（不带 to） He can swim. / You should rest. 无人称数变化 第三人称单数不加 -s She must go.（不说 musts） 否定加 not 情态动词 + not + 动词原形 You shouldn't be late. 疑问提前 情态动词 + 主语 + 动词原形? Can you help me? 二、should——建议与劝告 should 表示建议或劝告，意为「应当、应该」，可用于肯定句、否定句和疑问句；否定形式 shouldn't（should not）表示「不应该」。 You should drink more hot water. 你应该多喝热水。 You shouldn't stay up too late. 你不应该熬夜太晚。 Should I tell him the truth? 我应该告诉他真相吗？ 三、must——必须与禁止 must 意为「必须」，强调说话人的主观看法或规定、义务。 （一）must 引导一般疑问句的回答 肯定回答用 must；否定回答不能用 mustn't，而用 needn't 或 don't have to，意为「不必」。 —Must I finish it now? —Yes, you must. / No, you needn't (don't have to). ——我必须现在完成吗？——是的，必须。/ 不，不必。 （二）mustn't 表禁止 mustn't（must not）意为「一定不要、千万不要」，表示「不应该、禁止」，语气强烈。 You mustn't play on the road. It's dangerous. 你千万不要在马路上玩，很危险。 （三）must 与 have to 的区别 词语 侧重点 人称数变化 否定/疑问 must 多强调主观看法（说话人认为必须） 无人称数变化 直接 mustn't / Must...? have to 表示客观需要（外界条件迫使） 有人称数时态变化（has to/had to） 按行为动词变：don't have to / Do...have to? It's raining hard, so we have to stay at home. 雨下得很大，我们不得不待在家里。（客观需要） 【易错警示】mustn't 是「禁止做」，needn't 是「不必做」，二者意思完全不同：You mustn't go.（不许去）≠ You needn't go.（不必去）。 四、can——能力与许可 （一）两大含义 ① 表示能力，意为「能、会」；② 表示许可，意为「可以」（请求允许 / 给予许可）。否定形式 can't（cannot）表示「不能、不会、不可以」。 She can speak three languages. 她会说三种语言。（能力） —Can I use your pen? —Sure, here you are. ——我可以用你的钢笔吗？——当然，给你。（许可） （二）can 与 be able to 的辨析 两者都表示「能」。can 强调主观能力，只有现在式 can 和过去式 could；be able to 强调通过努力获得的客观能力，有人称和时态变化，可用于各种时态，因此将来时、完成时中只能用 be able to。 He will be able to drive after training next month. 下个月培训后他就能开车了。（将来时不用 can） 【注】can 的过去式是 could，表示过去的能力，如：He could swim at the age of five. 五、need——需要（情态动词与实义动词双重身份） （一）need 作情态动词 意为「需要、必要」，否定形式 needn't（need not）意为「不需要、不必」，多用于疑问句和否定句，后接动词原形。 You needn't worry about him. He is fine. 你不必为他担心，他很好。 Need I answer the question? 我需要回答这个问题吗？ （二）need 作实义动词 此时有人称和数的变化，用法同普通行为动词：后接名词、代词或带 to 的不定式（need to do）；其否定、疑问借助 do/does/did。 He needs some help. / She needs to have a rest. 他需要一些帮助。/ 她需要休息一下。 （三）need doing 主动表被动 当主语和 need 后的动词存在动宾（被动）关系时，用 need doing，主动形式表示被动含义，相当于 need to be done。 The bike needs repairing. = The bike needs to be repaired. 这辆自行车需要修理了。（车是「被修」） 六、had better——最好 had better 表示劝告或建议，意为「最好……」，后接动词原形，had 没有时态和人称变化。否定形式在 had better 后直接加 not，即 had better not do sth.。 You'd better see a doctor at once. 你最好马上去看医生。 You'd better not go out alone at night. 你晚上最好不要独自外出。 【易错警示】had better 后必须用动词原形：肯定 had better do；否定 had better not do（不加 to，也不说 don't had better）。 七、五大情态动词速查总表 情态动词 含义 否定形式 典型用法 should 应该（建议劝告） shouldn't 不应该 You should listen carefully. must 必须（主观/规定） mustn't 禁止；回答用 needn't 不必 Must I go? —No, you needn't. can 能、会；可以 can't 不能、不会、不可以 Can you swim? need 需要 needn't 不必（情态） You needn't hurry. had better 最好（建议） had better not do You'd better not be late. 八、典型例题精讲 【例1】—Must I hand in the report today? —No, you ______. You can do it tomorrow. A. mustn't B. needn't C. can't D. shouldn't 【答案】B 【解析】Must 提问的否定回答表示「不必」，用 needn't / don't have to；mustn't 表禁止，不能用于回答，选 B。 【例2】You ______ play with fire. It's too dangerous. A. needn't B. mustn't C. wouldn't D. may not 【答案】B 【解析】玩火是被「禁止」的，语气强烈，用 mustn't，选 B。 【例3】Your bike is broken. It needs ______. A. repair B. repairing C. to repair D. repaired 【答案】B 【解析】bike 与 repair 是被动关系，need doing 主动表被动，相当于 need to be repaired，选 B。 【例4】You'd better ______ late again. A. not be B. not to be C. don't be D. not being 【答案】A 【解析】had better not + 动词原形，be late「迟到」用 be，故选 A。 第二讲 综合演练 题型一 单项选择（每小题1分，共15分） 1. You ______ keep quiet in the reading room. A. can B. must C. need D. may 2. —Must I finish the work now? —No, you ______. You can do it tomorrow. A. mustn't B. needn't C. can't D. shouldn't 3. You ______ play on the road. It's dangerous. A. needn't B. mustn't C. wouldn't D. may not 4. You look tired. You ______ have a good rest. A. should B. would C. may D. need 5. —______ you swim? —Yes, I can. A. Must B. Should C. Can D. Need 6. He ______ speak a little English when he was five. A. can B. could C. must D. should 7. You ______ worry about him. He is fine. A. needn't B. mustn't C. can't D. wouldn't 8. You'd better ______ late for school again. A. not be B. not to be C. don't be D. not being 9. It's raining hard. We ______ stay at home. A. have to B. can C. may D. need 10. You ______ smoke here. Look at the sign "No Smoking". A. needn't B. mustn't C. wouldn't D. couldn't 11. —______ I use your dictionary? —Sure, here you are. A. Must B. Should C. Can D. Need 12. You'd better ______ to the doctor at once. A. go B. to go C. going D. went 13. The bike is broken. It needs ______. A. repair B. repairing C. to repair D. repaired 14. Students ______ wear school uniforms on weekdays. It's a rule. A. can B. must C. may D. need 15. After the training next month, he ______ drive a car. A. can B. will be able to C. must D. should 题型二 用所给动词的适当形式填空（每小题1分，共14分） 1. You should ______ (be) polite to old people. 2. You mustn't ______ (play) with fire. 3. He can ______ (speak) three languages. 4. You'd better ______ (not go) out alone at night. 5. You needn't ______ (worry) about the exam. 6. We should ______ (help) each other. 7. Must I ______ (clean) the room now? 8. The flowers need ______ (water). They are dry. 9. You shouldn't ______ (laugh) at others. 10. Can she ______ (dance) well? 11. You'd better ______ (see) a doctor. 12. He has to ______ (finish) his homework first. 13. You mustn't ______ (be) late again. 14. The room needs ______ (clean) every day. 题型三 完成句子 / 句型转换（每小题2分，共10题） A. 根据汉语意思完成句子（1—5题，每空一词） 1. 你必须在阅览室保持安静。 You ______ ______ quiet in the reading room. 2. 你千万不要在马路上玩耍。 You ______ ______ on the road. 3. 你最好别独自外出。 You'd ______ ______ go out alone. 4. 你不必为他担心。 You ______ ______ about him. 5. 她会说三种语言。 She ______ ______ three languages. B. 句型转换（6—10题，每空一词） 6. I must finish my homework first.（改为一般疑问句并作否定回答） ______ I finish my homework first? —No, you ______. 7. You should drink more water.（改为否定句） You ______ ______ more water. 8. He can play the piano.（改为一般疑问句并作肯定回答） ______ he play the piano? —______, he ______. 9. You'd better stay at home today.（改为否定句） You'd better ______ ______ at home today. 10. We must clean the classroom every day.（用 have to 改写为同义句） We ______ ______ clean the classroom every day. 答案与解析 题型一 单项选择 1. 【答案】B 【解析】阅览室规定「必须」保持安静，用 must 2. 【答案】B 【解析】Must 提问否定回答「不必」用 needn't 3. 【答案】B 【解析】马路玩耍是被禁止，mustn't 4. 【答案】A 【解析】建议对方休息，should 应该 5. 【答案】C 【解析】询问能力，用 Can 6. 【答案】B 【解析】when he was five 表过去，can 的过去式 could 7. 【答案】A 【解析】「不必」担心，needn't 8. 【答案】A 【解析】had better not + 动词原形 be 9. 【答案】A 【解析】下雨是客观需要，have to 不得不 10. 【答案】B 【解析】No Smoking 标志表示禁止，mustn't 11. 【答案】C 【解析】请求许可用 Can 12. 【答案】A 【解析】had better + 动词原形 go 13. 【答案】B 【解析】bike 与 repair 被动关系，need doing = need to be done 14. 【答案】B 【解析】校规要求「必须」穿校服，must 15. 【答案】B 【解析】next month 将来时，can 无将来式，用 will be able to 题型二 适当形式填空 1. 【答案】be 【解析】should + 动词原形，be polite 2. 【答案】play 【解析】mustn't + 动词原形 3. 【答案】speak 【解析】can + 动词原形 4. 【答案】not go 【解析】had better not + 动词原形 5. 【答案】worry 【解析】needn't + 动词原形 6. 【答案】help 【解析】should + 动词原形 7. 【答案】clean 【解析】Must + 主语 + 动词原形 8. 【答案】watering 【解析】花与浇水是被动关系，need doing 9. 【答案】laugh 【解析】shouldn't + 动词原形 10. 【答案】dance 【解析】Can + 主语 + 动词原形 11. 【答案】see 【解析】had better + 动词原形 12. 【答案】finish 【解析】have to + 动词原形 13. 【答案】be 【解析】mustn't + 动词原形 be 14. 【答案】cleaning 【解析】房间与打扫是被动关系，need cleaning = need to be cleaned 题型三 完成句子 / 句型转换 1. 【答案】must keep 【解析】必须 must + 动词原形 keep（keep quiet 保持安静） 2. 【答案】mustn't play 【解析】禁止 mustn't + 动词原形 3. 【答案】better not 【解析】had better not do，better 后加 not 4. 【答案】needn't worry 【解析】不必 needn't + 动词原形 5. 【答案】can speak 【解析】会（能力）can + 动词原形 6. 【答案】Must; needn't 【解析】Must 提前；否定回答「不必」用 needn't 7. 【答案】shouldn't drink 【解析】should 否定在其后加 not，shouldn't drink 8. 【答案】Can; Yes; can 【解析】can 疑问句把 can 提前；肯定回答 Yes, he can 9. 【答案】not stay 【解析】had better 否定为 had better not + 动词原形 10. 【答案】have to 【解析】客观「必须」用 have to，主语 we 用原形 have to 学科网（北京）股份有限公司 $