Unit3语法讲解及习题：Wh - 词 + 动词不定式（Infinitive after Wh-words）2026-2027学年沪教版英语（五四学制）九年级上册

该初中英语知识清单系统梳理了沪教英语（五四学制）九上Unit3“Wh-词+动词不定式”语法点，涵盖疑问词范围、句法功能、句式转换、易混点辨析及专项习题，搭建从基础结构到功能应用再到转换技巧的递进式学习支架。 清单通过“记忆口诀”（如“what有宾语，how缺宾语”）、“四步做题判断步骤”及“多样化题型”（单选、对话填空等）呈现知识体系，突出how/what辨析、why排除等重难点标注，培养学生语言能力和思维品质。设计“错题修正解析”（如第10题双宾语冲突分析）和“主从句主语一致性判定”，助力不同学生高效学习，为教师提供精准教学支持。

沪教英语（五四学制）九上Unit3语法讲解及习题： Wh - 词 + 动词不定式（Infinitive after Wh-words） 一、语法详细讲解 （一）可使用的 Wh 类疑问词 常用疑问词：what, when, where, which, who, whom, how； 注意：why 不能直接接 to do，不存在 why to do 这种结构。 结构公式： 例：where to travel（去哪里旅行）、what to pack（打包什么行李） （二）基本句法功能 该整体结构相当于一个名词短语，在句中可以充当宾语、表语、主语，最常作宾语。 1. 作宾语（出现频次最高） 常搭配动词：know, decide, wonder, tell, show, learn, ask, choose, figure out 等。 例句（旅行话题） ・I don’t know which scenic spot to visit first. 我不知道先游览哪一处景点。 ・She can’t decide what to put in her travelling bag. 她无法决定往旅行包里装什么东西。 2. 作表语 例句 ・The biggest problem is how to book cheap train tickets. 最大的难题是如何预订平价火车票。 3. 作主语（书面句式，日常使用偏少） 例句 ・When to set off for the trip hasn’t been decided yet. 何时动身开启旅程还没有敲定。 （三）句式转换（核心考点：复合句 ↔ 疑问词 + 不定式） 带有宾语从句（主语和主句主语一致），可以改写为 Wh - 词 + to do 结构。 1. 原宾语从句：I don’t know where I should stay overnight. 改写不定式结构：I don’t know where to stay overnight. 我不知道该在哪里留宿。 2. 原宾语从句：She can decide which route she will take. 改写不定式结构：She can decide which route to take. 她可以选择出行路线。 关键判定条件：主句主语和从句主语必须是同一个人，才能够完成转换；主语不一致，不能替换。 ❌ My mum tells me where she will go.（主从句主语不同，不能改成 where to go） （四）易混重难点辨析 1. 区分 how to do /what to do ・what to do：what 本身作 do 的宾语，后面不需要再加名词； I have no idea what to prepare.（what 充当 prepare 宾语） ・how to do：how 只作方式状语，do 后面必须补上宾语； I don’t know how to prepare travelling supplies.（supplies 为 do 的宾语） 记忆口诀：what 有宾语，how 缺宾语。 2. 排除 why to do 只能使用 why sb. do /why to do 不存在； ❌ I don’t know why to leave early. ✅ I don’t know why we leave early. 3. 多个疑问词不定式并列，第二个 to 可省略，正确句式： I haven’t decided where to go and what (to) buy. 我还没决定去哪里、要买什么。（并列不定式结构中，后一个不定式的 to 可以省略，语法合规） （五）例句 1. It’s so hard to decide where to go first on our sightseeing trip! 在观光旅程中，很难决定先去往何处。 2. I don’t know what to pack. 我不知道需要打包什么物品。 （六）做题判断步骤 1. 观察空格前后，判断是否需要名词性结构； 2. 区分疑问词：what 后面不加宾语，how 后面必须搭配宾语； 3. 核对主语是否统一，判断能否替换宾语从句； 4. 牢记 why 不可以接不定式 to do。 二、专项练习题 题型一：单项选择题 1. Lily can’t decide _________ for her coming mountain trip. A. what to prepare B. to prepare what C. what prepare D. prepare what 2. The guide will tell us _________ safe hiking roads in this forest. A. which choose B. which to choose C. to which choose D. choose which 3. I wonder _________ my travelling suitcase before tomorrow morning. A. when pack B. to when pack C. when to pack D. when packing 4. He has no idea _________ this old travel camera correctly. A. how to use it B. what to use C. what to use it D. how to use 5. Could you show me _________ I can ask for help when we get lost? A. to who turn B. who to turn to C. who turn to D. turn to who 6. The main trouble is _________ enough local snacks during our day trip. A. what buy B. buying what to C. what to buy D. to what buy 7. Many tourists don’t know _________ away from dangerous wild plants. A. how they keep B. what to keep C. what keep D. how to keep 8. Please tell me _________ the earliest coach to the scenic spot. A. which time catch B. when to catch C. to when catch D. when catch 9. She hasn’t made up her mind _________ as her travel souvenir. A. pick which gift B. which gift to pick C. to pick which gift D. which to pick gift 10. I haven’t learnt _________ proper travelling manners in foreign countries. A. how follow B. what to follow C. how to follow it D. what follow 11. Nobody can tell me _________ ahead of rainy weather on the journey. A. what we do B. to what do C. what to do D. what do 12. Do you know _________ for help if your luggage gets lost? A. whom ask B. ask whom C. to whom ask D. whom to ask 13. The hiker doesn’t know _________, because every path looks similar. A. where he can go B. where to go C. both A and B D. where go 14. We argue about _________ our camping tent beside the lake. A. what to put B. where put C. where to put D. to where put 15. I can’t figure out _________ for this long trip, so I ask my father for advice. A. why to pack B. which pack C. when pack D. what to pack 16. No one tells us _________ and _________ our travel plan. A. when to start; how to finish B. to when start; to how finish C. when start; how finish D. when starting; how finishing 题型二：对话填空 选用短语：A what to do B how to use it C when to wake you up D what to look out for E where to hike F what time to have breakfast Lisa: Dad, what if I oversleep tomorrow? Mr Green: Don’t worry, Lisa. Just let me know (17) _________. Lisa: I want to get up at 6 o’clock. Mr Green: All right! Did Mum tell you (18) _________? Lisa: Yes. Breakfast is served between 7:00 and 10:00. We’ll be the earliest guests! Dad, can I use your camera to take some photos during the trip? Mr Green: Of course. I’ll show you (19) _________ on the bus. Lisa: Dad, have you ever gone hiking before? Mr Green: I’ve been hiking once before. We followed a trail in a rainforest and were told (20) _________ in the forest to the fullest. It was really fascinating! Lisa: Sounds exciting! Dad, can you tell me (21) _________ before and during the hike? Oh, Dad, you haven’t told me (22) _________ tomorrow! Mr Green: No worries! We’ll talk about that on our way to the camp. But now it’s time for bed. Sweet dreams! 题型三：用合适的 Wh - 词 + to do 结构填空 23. She is confused about __________________（去哪里）for her one-day trip. 24. Could you advise me __________________（该准备什么）for mountain camping? 25. The young traveller does not know __________________（如何保护）himself from heavy rain. 26. No one decides __________________（何时出发）to the ancient town. 题型四：句型转换（ 将宾语从句改写为疑问词 + 不定式结构 ） 27. I don’t know which road I shall choose to reach the valley. _____________________________________________________________________ 28. She can’t work out when she will check in at the hotel. _____________________________________________________________________ 29. Do you know who we can ask for local travel information? _____________________________________________________________________ 题型五：句子改错（ 划出错误并写出正确答案 ） 30. The tourist has no idea why to leave the scenic area ahead of time. _____________________________________________________________________ 31. I don’t know how to prepare travelling goods, so I surf online for tips. _____________________________________________________________________ 题型六：短文选词填空 从 what to pack, where to travel, how to arrange 三个短语选词填空 Now my family are discussing our autumn vacation. We can’t agree on (32). My father wonders (33) to make our journey relaxing, while I am busy thinking about small gifts. 三、参考答案与详细解析 （一）单项选择题答案 + 解析 1. 答案：A 解析：固定结构 what to do，疑问词置于不定式前方，句意：莉莉无法决定为山地旅行准备什么。B、C、D 语序均不符合语法规则。 2. 答案：B 解析：which to choose（该选择哪一条），整体作动词 tell 的宾语，其余三项语序错误。 3. 答案：C 解析：when to pack（何时打包行李），属于疑问词加不定式作宾语。A 缺少 to，B 语序错乱，D 现在分词不能作宾语。 4. 答案：D 解析：how 本身作状语，宾语为本句的 this old travel camera，不需要再加 it；what 需要自身充当宾语，此处不能选用 what，选 D。 5. 答案：B 解析：who to turn to（可以求助的人），who 作介词 to 的宾语，为标准疑问词不定式结构。 6. 答案：C 解析：what 充当 buy 的宾语，结构为 what to buy，在句中作表语，其余选项语法不成立。 7. 答案：D 解析：how to keep（如何远离危险野生植物）；A 语法正确，但本单元考点为疑问词不定式，优先选 D。 8. 答案：B 解析：when to catch（什么时候搭乘最早大巴），符合出行话题语境，剩余选项均缺少不定式符号 to。 9. 答案：B 解析：which gift to pick（挑选哪一份礼品），名词置于疑问词与不定式中间，是规范句式。 10. 答案：A（修正原错误答案） 解析：本题为高频易错题。what 可独立作 do 类动词宾语，若选 B（what to follow），会与空格后已有宾语 proper travelling manners 构成双宾语，语法冲突、语义重复。本句已有完整宾语，只能用 how 表方式，正确结构为 how to follow（如何遵守礼仪），故选 A；C 选项多冗余代词 it，直接排除。 11. 答案：C 解析：what to do（需要做什么），what 作 do 的宾语，直接构成不定式短语。 12. 答案：D 解析：whom 是宾格，whom to ask（可以求助的对象），作宾语。 13. 答案：C 解析：where to go 等同于宾语从句 where he can go，两种句式全都正确，因此选 C。D 选项缺少 to，语法错误。 14. 答案：C 解析：where to put our camping tent（帐篷放置在哪里），疑问词 where 用来表示地点。 15. 答案：D 解析：why 不可以接不定式，排除 A；B、C 缺少不定式符号 to，句意：我不清楚旅途需要打包什么东西，选 D。 16. 答案：A 解析：并列结构 when to start 和 how to finish，为标准疑问词不定式结构。 （二）对话填空答案 17. C 18. F 19. B 20. E 21. D 22. A 解析梳理 17. 前文担心睡过头，对应 when to wake you up（几点叫醒你）； 18. 后文回答早餐时间，对应 what time to have breakfast（几点吃早餐）； 19. 前文提及使用相机，对应 how to use it（如何使用相机）； 20. 话题围绕徒步展开，对应 where to hike（徒步的地点）； 21. 询问徒步前后的注意事项，对应what to look out for（需要留意什么）； 22. 表示尚不明确明日需要做的事，对应 what to do（需要做什么）。 （三）用合适的Wh-词+to do结构填空参考答案 23. where to go 24. what to prepare 25. how to protect 26. when to set off （四）句型转换参考答案 27. I don’t know which road to choose to reach the valley. 28. She can’t work out when to check in at the hotel. 29. Do you know who to ask for local travel information? 解析：主句主语和宾语从句主语保持一致，直接删掉从句主语，将情态动词替换为 to 即可。 （五）改错题答案 30. 错误：why to leave → 修改：why we leave 解析：why 不能接动词不定式 to do，只能使用宾语从句。 31. 本句无语法错误 解析：句子结构合规，how 作方式状语，travelling goods 作 prepare 的宾语，契合 how to do + 宾语的核心语法规则，无需修改。网传改写为 what to prepare 为错误改法，会造成 prepare 语义重复、语法冗余，属于典型错题解析误区。 （六）短文填空答案 32. where to travel 33. how to arrange 解析：第一空一家人无法达成去往何处旅行的共识；第二空父亲思考如何规划行程，使旅途更加舒心。 ( 1 ) 学科网（北京）股份有限公司 $