Unit2 语法专练2025-2026学年人教版英语七年级下册

人教版7下第二单元语法专练 祈使句和情态动词 can, have to, must 第一部分：知识点详细讲解 一、祈使句详解 1. 什么是祈使句？ 祈使句用来表达命令、请求、建议、警告、禁止等。它的特点是通常省略主语 you，直接以动词原形开头。 例句： 请坐下。 Sit down, please. 打开窗户。 Open the window. 别说话。 Don't talk. 2. 祈使句的肯定形式 结构：动词原形 + 其他成分 常见用法： 表示命令 站出来！ Stand up! 快点！ Hurry up! 表示请求（常加please） 请帮我一下。 Help me, please. 请安静。 Be quiet, please. 表示建议 喝点水。 Drink some water. 休息一下。 Have a rest. 表示欢迎/邀请 请进。 Come in, please. 吃点儿苹果。 Have some apples. 3. 祈使句的否定形式 结构：Don't + 动词原形 + 其他成分 常见用法： 表示禁止 别跑。 Don't run. 别迟到。 Don't be late. 表示劝阻 别担心。 Don't worry. 别哭。 Don't cry. 表示警告 别碰！ Don't touch! 别开窗户。 Don't open the window. 4. Let's 开头的祈使句 Let's + 动词原形 表示建议（包括说话者自己） 咱们走吧。 Let's go. 咱们看电视吧。 Let's watch TV. 咱们别等了。 Let's not wait. (否定形式：Let's not + 动词原形) 5. 祈使句的反意疑问句 祈使句的反意疑问句通常用 will you 或 won't you。 请打开门，好吗？ Open the door, will you? 别迟到，行吗？ Don't be late, will you? 咱们走吧，好吗？ Let's go, shall we? (Let's开头用shall we) 二、情态动词 can 详解 1. can 的基本特征 情态动词 can 不能单独作谓语，必须和动词原形一起使用。没有人称和数的变化（不用 he cans）。 2. can 的三种核心用法 用法一：表示能力（会/能） 我会游泳。 I can swim. 她能说三种语言。 She can speak three languages. 我不会开车。 I can't drive. 用法二：表示请求和许可（可以） 我可以进来吗？ Can I come in? 你可以用我的笔。 You can use my pen. 对不起，你现在不能进去。 Sorry, you can't go in now. 用法三：表示可能性（可能） 那不可能是真的。 That can't be true. 现在可能会下雨。 It can rain anytime now. 3. can 的句型变化 肯定句：主语 + can + 动词原形 我会弹钢琴。 I can play the piano. 否定句：主语 + can + not (can't) + 动词原形 他不会说英语。 He can't speak English. 疑问句：Can + 主语 + 动词原形？ 你能帮我吗？ Can you help me? 三、情态动词 must 详解 1. must 的核心用法 用法一：表示必须（主观上认为有必要） 我必须现在走。 I must go now. 你必须在8点前回来。 You must be back before 8 o'clock. 用法二：表示禁止（mustn't = 绝对不可以） 你绝对不能在这儿停车。 You mustn't park here. 孩子们不能玩火。 Children mustn't play with fire. 用法三：表示肯定推测（一定） 你一定累了。 You must be tired. 他一定在家。 He must be at home. 2. must 的句型变化 肯定句：主语 + must + 动词原形 我们必须努力学习。 We must study hard. 否定句：主语 + must + not (mustn't) + 动词原形 你绝对不能告诉任何人。 You mustn't tell anyone. 疑问句：Must + 主语 + 动词原形？ 我必须现在做吗？ Must I do it now? 3. must 的否定回答 当问句用 Must 开头时，否定回答通常用 needn't 或 don't have to（不必），而不用 mustn't（因为 mustn't 表示禁止）。 Must I finish it now? 我必须现在完成吗？ No, you needn't. / No, you don't have to. 不，你不必。 （不能说：No, you mustn't，因为那是“你绝对不能”的意思） 四、情态动词 have to 详解 1. have to 与 must 的区别 have to 表示客观需要（因为外界因素不得不做） must 表示主观必须（自己认为有必要） 我眼睛不舒服，不得不戴眼镜。 I have to wear glasses.（客观需要） 为了漂亮，我必须戴隐形眼镜。 I must wear contact lenses.（主观意愿） 2. have to 有人称和时态变化 注意： have to 不是纯粹的情态动词，它有人称和时态的变化。 一般现在时： I/You/We/They have to go. He/She/It has to go. 一般过去时： had to（所有人都一样） 一般将来时： will have to 3. have to 的否定和疑问 否定句：don't/doesn't + have to（不必） 你不必现在来。 You don't have to come now. 他不必等。 He doesn't have to wait. 疑问句：Do/Does + 主语 + have to？ 我必须现在做吗？ Do I have to do it now? 她得走了吗？ Does she have to go? 五、can, must, have to 的对比总结 情态动词 核心含义 否定形式及含义 疑问句形式 特点 can 能/可以 can't（不能/不可以） Can + 主语？ 表示能力、许可、可能性 must 必须（主观） mustn't（绝对不能/禁止） Must + 主语？ 主观意志，无时态变化 have to 不得不（客观） don't/doesn't have to（不必） Do/Does + 主语 + have to？ 有人称和时态变化 第二部分：分层强化练习 一、单项选择 1. ______ quiet, please. The baby is sleeping. A. Be B. To be C. Being D. Is 2. —______ I use your pen? —Of course. Here you are. A. Must B. Can C. Have to D. May 3. You ______ smoke here. It's a hospital. A. can B. must C. mustn't D. don't have to 4. ______ late for school again, Tom. A. Not be B. Don't be C. Be not D. Don't 5. My eyes are not good. I ______ wear glasses. A. must B. can C. have to D. may 6. —Must I finish my homework now? —No, you ______. You can do it tomorrow. A. mustn't B. can't C. don't have to D. needn't to 7. ______ let's go to the park. ______ open the door? A. Let's / Will you B. Let / Shall we C. Let's / Shall we D. Let / Will you 8. She ______ speak three languages: English, French and Chinese. A. can B. must C. have to D. need 9. You look pale. You ______ see a doctor. A. can B. must C. have to D. should 10. ______ afraid. I'll help you. A. Not B. Don't C. Don't be D. Be not 11. We ______ hurry up. The train leaves in 10 minutes. A. can B. must C. have to D. may 12. ______ I come in? —Yes, please. A. Must B. Can C. Have to D. Do 13. You ______ tell anyone. It's a secret. A. don't have to B. can't C. mustn't D. needn't 14. ______ me a hand, please? A. Can give B. Can you give C. You give D. Give you 15. He ______ get up early every day because he lives far from school. A. must B. can C. has to D. have to 16. ______ the window. It's too cold outside. A. Open B. Don't open C. Not open D. No open 17. —Can you play the guitar? —Sorry, I ______. A. can B. can't C. mustn't D. don't 18. Let's ______ football this afternoon. A. play B. to play C. playing D. plays 19. You ______ worry about me. I'm fine. A. don't have to B. mustn't C. can't D. need 20. ______ some water. You look thirsty. A. Drink B. To drink C. Drinking D. Drinks 二、用所给词的适当形式填空 1. ________ (not talk) in class, please. 2. She ________ (can) swim when she was five years old. 3. You look tired. You ________ (have to) stop working. 4. ________ (be) careful! The floor is wet. 5. He ________ (have to) wear glasses because he can't see clearly. 6. We ________ (must) be quiet in the library. 7. ________ (not run) in the hallway. 8. —Must we finish the work today? —No, you ________ (need). 9. She ________ (can not) come to the party because she's ill. 10. Let's ________ (go) shopping this weekend. 11. You ________ (must not) play with fire. It's dangerous. 12. He ________ (have to) get up at 6:00 every morning. 13. ________ (not be) late for the meeting. 14. I ________ (can) ride a bike, but I ________ (can not) drive a car. 15. You ________ (not have to) buy me a gift. Just come to the party. 16. ________ (open) the door, please. It's hot inside. 17. She ________ (have to) take the bus to work yesterday because her car broke down. 18. ________ (shall) we go to the cinema? 19. You ________ (must) finish your homework before you watch TV. 20. ________ (not forget) to lock the door when you leave. 三、句型转换 1. You must be quiet in the library. (改为祈使句) ________ ________ in the library. 2. I can swim. (改为否定句) I ________ ________. 3. You have to finish the work today. (改为一般疑问句) ________ I ________ ________ finish the work today? 4. Open the window. (改为否定祈使句) ________ ________ the window. 5. He can speak English. (改为一般疑问句) ________ ________ speak English? 6. We must go now. (改为否定句) We ________ ________ now. (用“不必”的意思) 7. Let's play games. (改为反意疑问句) Let's play games, ________ ________? 8. She can dance well. (改为否定句) She ________ ________ well. 9. You mustn't smoke here. (改为祈使句) ________ ________ here. 10. I have to get up early. (改为否定句) I ________ ________ ________ get up early. 11. Can you help me? (改为祈使句) ________ me, please. 12. They have to wear uniforms at school. (改为一般疑问句) ________ they ________ ________ wear uniforms at school? 13. Be quiet. (改为反意疑问句) Be quiet, ________ ________? 14. He can play the piano. (对划线部分提问) ________ ________ he ________? 15. You don't have to wait for me. (改为同义句) You ________ ________ for me. 四、改错题 1. Not run in the classroom. ________ 应改为 ________ 2. He cans play basketball very well. ________ 应改为 ________ 3. You don't have to smoke here. It's a hospital. ________ 应改为 ________ 4. Let's to go to the park. ________ 应改为 ________ 5. She have to finish her homework first. ________ 应改为 ________ 6. Be not late for class. ________ 应改为 ________ 7. —Must I come back before 10? —No, you mustn't. ________ 应改为 ________ 8. He doesn't has to work on Sundays. ________ 应改为 ________ 9. Opens the door, please. ________ 应改为 ________ 10. You must to study hard. ________ 应改为 ________ 五、根据汉语意思完成句子 1. 请安静。 ________ ________, please. 2. 我会弹吉他。 I ________ ________ the guitar. 3. 你绝对不能告诉任何人。 You ________ ________ anyone. 4. 咱们去看电影吧。 ________ ________ to the movies. 5. 他每天不得不早起。 He ________ ________ ________ up early every day. 6. 别担心，我会帮你的。 ________ ________, I'll help you. 7. 我可以进来吗？ ________ I ________ in? 8. 你不必现在做决定。 You ________ ________ ________ make a decision now. 9. 请打开窗户，好吗？ ________ the window, ________ ________? 10. 她必须穿校服吗？ ________ she ________ ________ wear a school uniform? 第三部分：参考答案与详细解析 一、单项选择答案与解析 1. A 祈使句以动词原形开头，Be quiet是固定搭配“安静”。 2. B 询问许可，用Can I...？最常用。May更正式，但can更口语化。 3. C 医院禁止吸烟，用mustn't（绝对不可以）。 4. B 祈使句的否定形式：Don't + 动词原形。Don't be late是固定搭配。 5. C 眼睛不好，不得不戴眼镜，表示客观需要，用have to。 6. C Must开头的一般疑问句，否定回答用don't have to或needn't（不必）。D项needn't to是错误形式（needn't后直接加动词原形）。 7. C Let's开头的祈使句，反意疑问句用shall we。 8. A 表示能力“会”，用can。 9. B 脸色苍白，主观上认为“必须”看医生，用must。 10. C Don't be afraid是祈使句否定形式，意为“别害怕”。 11. B 火车10分钟后开，主观上认为“必须”快点，用must。 12. B 询问许可，用Can I。 13. C 既然是秘密，就“绝对不能”告诉别人，用mustn't。 14. B 请求帮助，用Can you give me a hand? 15. C 住得远，所以“不得不”早起，客观需要，主语是he，用has to。 16. B 外面太冷，所以“别开”窗户，祈使句否定用Don't open。 17. B 对Can you...？问句的否定回答用can't。 18. A Let's后接动词原形。 19. A 不必担心，用don't have to（没必要）。mustn't是“禁止”，can't是“不能”，都不合适。 20. A 祈使句，用动词原形Drink开头。 二、用所给词的适当形式填空答案与解析 1. Don't talk 祈使句否定形式：Don't + 动词原形。 2. could 表示过去的能力，用can的过去式could。 3. have to 表示客观需要“不得不”，主语是You，用have to。 4. Be 祈使句肯定形式，用动词原形Be。 5. has to 客观需要“不得不”，主语是He，用has to。 6. must 情态动词后接动词原形，must be quiet。 7. Don't run 祈使句否定形式。 8. needn't / don't have to Must问句的否定回答。 9. cannot / can't 表示“不能”，can的否定形式。 10. go Let's后接动词原形。 11. mustn't 表示禁止“绝对不能”。 12. has to 客观需要“不得不”，主语He。 13. Don't be 祈使句否定形式，Don't be late。 14. can / cannot 表示能力“会”和“不会”。 15. don't have to 表示“不必”。 16. Open 祈使句肯定形式。 17. had to yesterday是过去时间，have to的过去式是had to。 18. Shall Shall we...？是建议的句型。 19. must 表示主观必须。 20. Don't forget 祈使句否定形式。 三、句型转换答案与解析 1. Be quiet 将must be quiet改为祈使句，直接用Be quiet。 2. can't swim can的否定形式。 3. Do / have to have to的一般疑问句用Do开头。 4. Don't open 祈使句否定形式。 5. Can he 将can提至句首。 6. don't have to must的否定用don't have to表示“不必”。 7. shall we Let's开头的反意疑问句用shall we。 8. can't dance can的否定形式。 9. Don't smoke 将mustn't smoke改为祈使句否定。 10. don't have to have to的否定形式。 11. Help 将Can you help me改为祈使句Help me。 12. Do / have to have to的一般疑问句。 13. will you 祈使句的反意疑问句用will you。 14. What can / do 对play the piano提问，用What can he do。 15. needn't wait don't have to相当于needn't。 四、改错题答案与解析 1. Not 应改为 Don't 祈使句否定用Don't + 动词原形。 2. cans 应改为 can 情态动词后没有第三人称单数变化。 3. don't have to 应改为 mustn't 医院禁止吸烟，用mustn't。 4. Let's to go 应改为 Let's go Let's后接动词原形。 5. have to 应改为 has to 主语She，用has to。 6. Be not 应改为 Don't be 祈使句否定形式。 7. mustn't 应改为 don't have to / needn't Must问句否定回答用“不必”。 8. doesn't has to 应改为 doesn't have to 助动词后动词用原形。 9. Opens 应改为 Open 祈使句用动词原形。 10. must to 应改为 must 情态动词后直接加动词原形。 五、根据汉语意思完成句子答案与解析 1. Be quiet 祈使句肯定形式。 2. can play 表示能力“会”。 3. mustn't tell 表示禁止“绝对不能”。 4. Let's go Let's + 动词原形。 5. has to get 客观需要“不得不”，主语He，用has to。 6. Don't worry 祈使句否定形式。 7. Can / come 询问许可。 8. don't have to 表示“不必”。 9. Open / will you 祈使句+反意疑问句。 10. Does / have to have to的一般疑问句。 学科网（北京）股份有限公司 $