Unit 4 语法 Word Power 2025-2026学年译林版八年级英语上册

译林英语八上 Unit 4 语法+Word Power 精讲+分级习题 （附答案解析） 一、语法：祈使句 + should & had better 1. 祈使句（Imperative sentences） （1）核心用法 用于发出命令、提出要求或建议，主语通常省略。 肯定形式：以动词原形开头。 否定形式：在动词原形前加 don't。 礼貌表达：句中或句末加 please；句末时需用逗号隔开。 建议一起做某事：用 Let's + 动词原形。 （2）句型结构 类型 结构 例句 肯定祈使句 动词原形 + 其他 Put the pieces of wood together. 否定祈使句 Don't + 动词原形 + 其他 Don't mix them up. 礼貌祈使句 Please + 动词原形 + 其他 / 动词原形 + 其他, please Please hand the tools to me. / Open the window, please. 建议祈使句 Let's + 动词原形 + 其他 Let's put the pieces of wood together. 2. should & had better 提建议 （1）核心用法 should：表示“应该”，语气较温和，用于给出建议或表达责任。 had better：表示“最好”，语气比 should 更强，带有警告或强调必要性。 两者都接动词原形，无人称和数的变化。 否定形式：should not/shouldn't；had better not。 （2）句型结构 用法 结构 例句 肯定建议 should / had better + 动词原形 You should mix the paint well. / We'd better clean the bird box first. 否定建议 shouldn't / had better not + 动词原形 You shouldn't go too fast. / You'd better not get too much paint on the brush. 二、Word Power 专题：前缀 un- in- im- 构词法 1. 核心前缀含义 这些前缀用于构成形容词的反义词，表示“不、非、无”。 前缀 形容词 反义词 备注 un- lucky; usual; tidy unlucky; unusual; untidy 最常用，多用于普通形容词 in- correct; complete; active incorrect; incomplete; inactive 多用于以 c、p 开头的形容词 im- possible; polite; perfect impossible; impolite; imperfect 用于以 p 开头的形容词 2. 特殊变化 able → unable（而非 inable） patient → impatient（而非 inpatient） 3. 例句 It’s unusual to find me without a DIY job to do. It’s impossible to finish a DIY job if you’re not patient. Your room is really untidy—things are all over the floor. 三、习题（共50题） 第一部分：基础过关题（20题） 题型1：祈使句填空（8题） 1. __________ (cut) the paper into small pieces. 2. __________ (not mix) the different colours together. 3. __________ (please pass) me the scissors. 4. __________ (look) at the instructions carefully. 5. __________ (let's) make a model plane together. 6. __________ (keep) the tools in a safe place. 7. __________ (not touch) the wet paint. 8. __________ (write) your name on the card. 题型2：should & had better 填空（6题） 9. You __________ (finish) your homework before watching TV. 10. We __________ (not go) out in the heavy rain. 11. He __________ (be) more careful with the knife. 12. You __________ (take) a break after working for hours. 13. They __________ (not eat) too much junk food. 14. She __________ (ask) the teacher for help if she doesn't understand. 题型3：Word Power 填空（6题） 15. It's __________ (usual) to see snow in summer. 16. His answer is __________ (correct). Please check it again. 17. It's __________ (possible) to finish the work in 10 minutes. 18. Don't be __________ (polite) to others. 19. The room is __________ (tidy). Please clean it up. 20. He felt __________ (lucky) because he lost his keys. 第二部分：能力提升题（20题） 题型1：句型转换（8题） 21. Please pass me the glue.（改为否定句） __________ __________ __________ me the glue. 22. Let's make a cake.（改为否定句） Let's __________ __________ a cake. 23. You should read the instructions first.（改为同义句） You __________ __________ read the instructions first. 24. You had better not play with fire.（改为同义句） You __________ __________ play with fire. 25. Be quiet.（改为礼貌表达） __________ __________ __________, please. 26. Don't be late.（改为同义句） You __________ __________ __________ late. 27. Let's go shopping.（改为一般疑问句） __________ __________ go shopping? 28. You should practice more.（改为否定句） You __________ __________ practice more. 题型2：单项选择（12题） 29. __________ the window, please. It's too hot. A. Open B. Opens C. Opening D. Opened 30. __________ talk in class. A. Not B. Don't C. No D. Doesn't 31. Let's __________ a DIY project together. A. do B. doing C. to do D. did 32. You __________ finish your homework now. A. had better B. had better to C. should to D. better 33. You __________ eat too much sugar. It's bad for your teeth. A. should B. shouldn't C. had better D. had better not 34. It's __________ to climb the tree. It's dangerous. A. possible B. impossible C. impolite D. unsafe 35. His answer is __________. He made a mistake. A. correct B. incorrect C. uncorrect D. inpossible 36. The room is __________. Please clean it. A. tidy B. untidy C. tidyly D. untidyly 37. __________ me your DIY work, please. A. Show B. Shows C. Showing D. To show 38. You __________ ask for help if you need it. A. should B. shouldn't C. had better not D. better 39. Let's __________ the instructions again. A. read B. reading C. to read D. reads 40. It's __________ to finish the work alone. Let's ask for help. A. possible B. impossible C. polite D. impolite 第三部分：拓展拔高题（10题） 题型1：短文填空（5题） 阅读短文，用括号内单词的正确形式填空（祈使句/should & had better/前缀） __________ (listen) to the teacher carefully when you learn DIY. You __________ (not rush) when you use tools. It's __________ (possible) to do a good job if you're __________ (patient). You __________ (ask) for help if you have problems. 题型2：改错（5题） 46. Don't to touch the wet paint. 错误：__________ 改正：__________ 47. You should to finish your homework. 错误：__________ 改正：__________ 48. It's unpolite to talk loudly in the library. 错误：__________ 改正：__________ 49. Let's not to go out today. 错误：__________ 改正：__________ 50. You had better not to eat too much. 错误：__________ 改正：__________ 四、答案与完整解析 第一部分：基础过关题答案与解析 1. 答案：Cut 解析：祈使句肯定形式，用动词原形。 2. 答案：Don't mix 解析：祈使句否定形式，用 don't + 动词原形。 3. 答案：Please pass / Pass 解析：礼貌祈使句，可用 please 开头或结尾。 4. 答案：Look 解析：祈使句肯定形式，用动词原形。 5. 答案：Let's 解析：建议一起做某事，用 Let's + 动词原形。 6. 答案：Keep 解析：祈使句肯定形式，用动词原形。 7. 答案：Don't touch 解析：祈使句否定形式，用 don't + 动词原形。 8. 答案：Write 解析：祈使句肯定形式，用动词原形。 9. 答案：should / had better 解析：表示建议“应该/最好完成作业”。 10. 答案：had better not / shouldn't 解析：表示建议“最好不要/不应该在大雨中外出”。 11. 答案：should / had better be 解析：表示建议“应该/最好更小心”。 12. 答案：should / had better take 解析：表示建议“应该/最好休息一下”。 13. 答案：shouldn't / had better not eat 解析：表示建议“不应该/最好不要吃太多垃圾食品”。 14. 答案：should / had better ask 解析：表示建议“应该/最好向老师求助”。 15. 答案：unusual 解析：usual 加前缀 un- 表示“不寻常的”。 16. 答案：incorrect 解析：correct 加前缀 in- 表示“不正确的”。 17. 答案：impossible 解析：possible 加前缀 im- 表示“不可能的”。 18. 答案：impolite 解析：polite 加前缀 im- 表示“不礼貌的”。 19. 答案：untidy 解析：tidy 加前缀 un- 表示“不整洁的”。 20. 答案：unlucky 解析：lucky 加前缀 un- 表示“不幸的”。 第二部分：能力提升题答案与解析 21. 答案：Please don't pass 解析：祈使句否定形式，please 可放在句首。 22. 答案：not make 解析：Let's 的否定形式为 Let's not + 动词原形。 23. 答案：had better 解析：should 和 had better 均可表示建议。 24. 答案：shouldn't 解析：had better not 和 shouldn't 均可表示否定建议。 25. 答案：Be quiet 解析：礼貌表达，please 放在句末。 26. 答案：shouldn't be / had better not be 解析：祈使句否定形式转换为 shouldn't 或 had better not。 27. 答案：Shall we 解析：Let's 句型的一般疑问句形式为 Shall we ...?。 28. 答案：shouldn't 解析：should 的否定形式为 shouldn't。 29. 答案：A 解析：祈使句肯定形式，用动词原形。 30. 答案：B 解析：祈使句否定形式，用 don't。 31. 答案：A 解析：Let's 后接动词原形。 32. 答案：A 解析：had better 后接动词原形。 33. 答案：B / D 解析：表示否定建议，shouldn't 和 had better not 均可。 34. 答案：D 解析：表示“不安全的”，用 unsafe。 35. 答案：B 解析：correct 的反义词为 incorrect。 36. 答案：B 解析：tidy 的反义词为 untidy。 37. 答案：A 解析：祈使句肯定形式，用动词原形。 38. 答案：A 解析：表示建议“应该求助”，用 should。 39. 答案：A 解析：Let's 后接动词原形。 40. 答案：B 解析：表示“不可能独自完成”，用 impossible。 第三部分：拓展拔高题答案与解析 短文填空答案 41. Listen 42. shouldn't / had better not rush 43. impossible 44. impatient 45. should / had better ask 短文填空解析 41. 祈使句肯定形式，用动词原形 Listen。 42. 否定建议，用 shouldn't rush 或 had better not rush。 43. possible 加前缀 im- 表示“不可能的”。 44. patient 加前缀 im- 表示“不耐烦的”。 45. 肯定建议，用 should ask 或 had better ask。 改错答案与解析 46. 错误：to touch；改正：touch 解析：祈使句否定形式为 don't + 动词原形，不需要 to。 47. 错误：to finish；改正：finish 解析：should 后接动词原形，不需要 to。 48. 错误：unpolite；改正：impolite 解析：polite 的反义词为 impolite，而非 unpolite。 49. 错误：to go；改正：go 解析：Let's not 后接动词原形，不需要 to。 50. 错误：to eat；改正：eat 解析：had better not 后接动词原形，不需要 to。 ( 1 ) 学科网（北京）股份有限公司 $