基础动词用法 情态动词系统讲解-2025-2026学年高考复习高中英语语法知识点全解（沪教版）

高中沪教上海版 【语法专版】 基础动词用法 语法专版 【专题】情态动词系统讲解 沪教上海版高中英语语法全解 考频分析 沪教上海版高中英语中，情态动词是基础动词用法中的重点语法模块，考频占词法总量的15%左 右，贯穿试卷所有核心题型：单项选择2-3题、完形填空2-3题、语法填空1-2题、书面表达核心 考察，直接影响句子语气表达与语境适配性。在语境理解类题目中，情态动词的推测用法、语气差 异及情景搭配往往是解题关键。 考查内容 。基本词义辨析：can/could、may/might、.must/have to、shal/should、wil/would、need/dare的核心语 义与语气强弱对比 ●推测用法：情态动词表肯定推测(must/can't/could/may/might)与否定推测的语境判断，不同时态下 的结构（情态动词+be doing/have done) 。特殊用法与固定搭配：情态动词+完成时表虚拟或未实现的动作(should have done/needn't have done),情态动词在疑问句中的委婉表达与回答规则 知识点一：情态动词的分类及基础用法 1.能力与许可类情态动词 1.can/could:表示“能/会（能力）”或“可以（许可）”，could为can的过去式或委婉形式 ·例句： 1.She can speak three languages.(表能力) 2.Could I use your pen?(委婉表许可) 2.推测与可能性类情态动词 1.may/might:表示“可能/可以（许可）”，might语气比nay更弱 2.must:表示“肯定/一定（肯定推测)”，否定推测用can’t(不可能) 1 高中沪教上海版 【语法专版】 基础动词用法 。例句： 1.He may come tomorrow.(表可能性) 2.This must be your book.(肯定推测) 3.义务与建议类情态动词 1.must/have to:must表主观“必须”，have to表客观“不得不” 2.should/ought to:表示“应该（建议或义务）” ·例句 1.You must follow the rules..(主观必须) 2.You should see a doctor.(表建议) 4.情态动词的特殊用法 1.need:既可作情态动词(“需要”，用于否定/疑问句)，也可作实义动词(need to do) 2.had better:表示“最好做某事”，后接动词原形 。例句： 1.You needn't worry.(情态动词，否定) 2.You'd better hurry.(had better用法) 知识点二：情态动词基本用法与常见搭配 1.can/could(能力、许可、请求) 1.基本含义 。c:表示现在的能力(“能，会”)、许可（口语中，“可以”）、否定推测(“不可能”) 。could:表示过去的能力、委婉请求（比can更礼貌）、可能性推测(“可能”，语气弱于may) 2.结构与例句 ●能力：She can speak three languages.(她会说三种语言。) ·过去能力：I could swim when I was five.(我五岁时会游泳。) ·许可：Can I use your pen'?(我能用你的笔吗？) 。委婉请求：Could you help me carry the box?(你能帮我搬箱子吗？) ·否定推测：He can't be at home now-he left for Beijing this morning.(他现在不可能在家—他 今早去北京了。) 2.may/might(许可、可能性、请求) 2 高中沪教上海版 【语法专版】 基础动词用法 1.基本含义 ·may:表示许可（正式，“可以”）、肯定推测(“可能”)、请求允许（语气比can正式） 。might:表示可能性推测（比may语气弱，“也许”）、委婉请求（比may更客气） 2.结构与例句 。许可：You may leave the classroom after finishing the test..(考试结束后你可以离开教室。) 。推测：It may rain tomorrow,so take an umbrella.(明天可能下雨，带把伞吧。) 。委婉请求：Might I borrow your dictionary for a moment?(我可以借你的字典用一下吗？) ·弱推测：She might not come to the party-一she's been busy lately..(她也许不来派对一她最近很 忙。) 3.must/have to(必须、肯定推测) 1.基本含义 。ust:表示主观义务(“必须”，强调说话人意志)、肯定推测(“一定”，语气强烈) 。have to:表示客观需要(“不得不”，受外界条件限制)，过去式为had to 2.否定形式与区别 。nustn't:表示“禁止”(You mustn’t smoke here.禁止吸烟。) 。don'thave to:表示“不必”(You don'thave to get up early on weekends.周末你不必早起。) 3.例句 ●主观必须：We must follow the school rules.(我们必须遵守校规。) 。客观需要：I have to go to the doctor because I have a fever.(我不得不去看医生，因为我发烧了。) 。肯定推测：The light is on,so he must be in the office..(灯亮着，他一定在办公室。) 4.should/ought to(应该、建议、责任) 1.基本含义 ●should/ought to:表示建议(“应该”)、责任(“理应”)、推测(“按理说”)，ought to语气比should 稍强，后接动词原形 2.结构与例句 。建议：You should study harder for the exam.(你应该为考试更努力学习。) 。责任：Teachers ought to care about their students.(老师理应关心学生。) 。推测：He should be here by now-he left an hour ago.(他现在应该到了一他一小时前就出发了。) ●否定建议：You shouldn’t eat too much junk food..(你不应该吃太多垃圾食品。) 3 高中沪教上海版 【语法专版】 基础动词用法 5.need(需要、必要) 1.基本用法 。作情态动词：常用于否定句和疑问句，意为“需要”，否定形式ne’t(“不必”)，无过去式 ·作实义动词：后接不定式(todo),有人称和时态变化，否定形式用don't/doesn't/didn’tneed 2.例句 。情态动词：Need I finish the work today?(我今天需要完成工作吗？)-No,you needn't.You can do it tomorrow.(不必，你可以明天做。) ·实义动词：She needs to buy a new notebook.(她需要买一个新笔记本。)He didn'tneedto come early yesterday..(他昨天不必早来。) 6.wil/would（意愿、习惯、请求) 1.基本含义 ·wl:表示意愿(“愿意”)、习惯(“总是”)、请求（口语中，“请”)、将来时助动词（已在时态 中讲解，此处侧重情态含义) ·would:表示过去习惯(“过去常常”)、委婉请求（比wll礼貌）、意愿（过去时） 2.例句 ·意愿：I will help you with your English..(我愿意帮你学英语。) ·过去习惯：When he was young,he would go fishing every weekend.(他年轻时每个周末都会去钓 鱼。) 。委婉请求：Would you please pass the salt?(请把盐递给我好吗？) 。习惯动作：She will often sit by the window and read.(她常常坐在窗边看书。) 7.had better(最好做某事) l.基本结构：had better+动词原形（否定形式：had better not+动词原形） 2.含义与例句 。表示建议或警告(“最好…，否则…”)，语气较强，用于口语 ·You had better wear warm clothes-一it's cold outside.(你最好穿暖和点，外面冷。) 。You had better not late for the meeting.(你开会最好不要迟到。) 知识点三：情态动词 1.表能力（中考基础） 4 高中沪教上海版 【语法专版】 基础动词用法 1.can(能/会)→例句：She can speak English fluently. 2.could(过去能/委婉请求)→例句：I could swim when I was five. 3.be able to(强调通过努力实现)→例句：He was able to pass the exam after studying hard. 2.表许可（中考核心) 1.nay(可以/请求许可)→例句：May I borrow your pen? 2.might(语气更委婉)→例句：Might I leave the room for a moment? 3.can（非正式许可)→例句：You can use my dictionary. 3.表推测（中考难点） 1.must（肯定推测，一定)→例句：He must be at home now. 2.can't（否定推测，不可能)→例句：It can't be true. 3.nay/might(可能性推测，可能)→例句：She may come to the party tonight. 4.表义务/建议（中考高频） 1.should(应该)→例句：You should study hard. 2.ought to(应该，较正式)→例句：We ought to help each other.. 3.had better(最好)→例句：You had better go to bed early. 5.表意愿/必要性（中考易错)》 1.will(愿意/将要)→例句：I will help you. 2.would(过去意愿/委婉请求)→例句：Would you please open the window? 3.need(需要)→例句：You needn't worry about it. 考法精析 考法一：情态动词表推测的时态差异 核心：根据语境判断推测的时间（现在/过去），选择正确结构（情态动词+动词原形情态动词+have+ 过去分词) 真题1（语法填空）： She_(see)the movie before,because she can describe the plot in detail. 答案：must have seen 解析：由语境“她能详细描述剧情”可知是对过去情况的肯定推测，结构为“must+have+过去分 5 高中沪教上海版 【语法专版】 基础动词用法 词”，see的过去分词为seen。 真题2（完形填空）： The light is on in his room.He be studying now. A.must B.must have C.may have D.can 答案：A 解析：由时间标志词“now”可知是对现在情况的推测，结构为“情态动词+动词原形”，“ust be studying”表示“肯定在学习”，符合语境。 考法二：情态动词表推测的时态差异与语境应用 核心：结合上下文时间线索或逻辑关系，判断对现在/过去情况的推测，选择正确的情态动词结构 (情态动词+原形have+过去分词) 真题1（语法填空）： The ground is all wet.It_(rain)heavily last night. 答案：nust have rained 解析：由时间标志词“last night”可知是对过去情况的推测，根据“地面全湿”的语境，用must have- 过去分词表肯定推测。 真题2（单项选择)： -Where is Lucy?I can't find her anywhere. -She_be in the library.She often reads there after school. A.must B.must have C.may have D.can 答案：A 解析：由语境“现在找不到Lucy”及“她经常放学后在图书馆读书”可知是对现在情沉的推测，用 ust+动词原形表肯定推测。 考法三：情态动词的综合语境辨析与应用 核心：结合语境区分近义情态动词的细微差异（如may/might可能性程度、must/have to主客观区 别)，掌握不同情态动词在推测、许可、建议等场景中的正确使用 真题1（单项选择)： -I borrow your dictionary?I left mine at home. -Sure,here you are. A.Must B.Should C.May D.Need 答案：C 解析：根据语境“请求许可借字典”，需用表许可的情态动词may:must表“必须”，should表“应 该”，need表“需要”，均不符合请求许可的语境。 真题2（语法填空）： You_(not worry)about the test.You have prepared well enough. 答案：needn't worry 解析：根据语境“不必担心考试（因为准备充分）”，表“不必”用情态动词needn't,后接动词原 形：此处无需用实义动词形式，因题干无明确时态标志且强调主观必要性。 6 高中沪教上海版 【语法专版】基础动词用法 解题小妙招 情态动词推测妙招 推测时间先判断，现在过去要分清： 现在推测原形跟，must may might都行； 过去推测看完成，have加上过去分词： 肯定must很确定，否定can't表不行： should have本应做，虚拟语气责备情： 语境逻辑是关键，标志词语常提醒。 真题演练 演练一：单项选择试题（共10题） 1.The door is locked.He_be at home now. A.mustn't B.can't C.might D.should 2.-I borrow your dictionary? -Sure,here you are. A.Must B.Need C.May D.Should 3.Youhave told me the truth earlier.Now it's too late. A.should B.must C.can D.may 4.She looks happy.Shehave passed the exam. A.can't B.must C.might not D.needn't 5.If you_harder,you could have won the competition. A.work B.worked C.had worked D.have worked 6.-Must I finish the report today? -No,you_.You can do it tomorrow. A.mustn't B.needn't C.can't D.shouldn't 7.Itrain later,so take an umbrella with you. A.must B.need C.might D.should 8.They_be in the classroom.I saw them playing outside just now. A.mustn't B.can't C.should D.may 9.You-not smoke in public places.It's against the law. A.might B.need C.must D.could 10.Hespeak French fluently when he was five. A.can B.could C.must D.should 7 高中沪教上海版 【语法专版】 基础动词用法 演练二：填空试题（共10题） 1.We一(ot leave)yet-the film hasn't started.(提示：表“不必”，用neen't leave) 2.You_be)more careful!The road is slippery.(提示：责备语气“本应该”，用should have been) 3.IfI_kuow)you were coming,I would have prepared dinner.(提示：虚拟语气“本可以知道”，用 could have known) 4.She一(finish)the work yesterday.I saw her working late.(提示：对过去肯定推测，用must have finished) 5.You_(not park)here.It'sano-parking zone.(提示：表“禁止”，用mustn’t park) 6.They一(go)to the party,but they decided to stay home..(提示：“本可以去”，用could have gone) 7.He一(be)at the office now.His car is still in the parking lot.(提示：对现在肯定推测，用must be) 8.You_(cal)your mother.She has been worried about you.(提示：表“应该”，用should call) 9.She_(not see)the movie before.She asked me about the plot.(提示：对过去否定推测，用can'thave seen) l0.We一(tat)the meeting earlier..Now we're running late.(提示：“本应该开始”，用should have started) 演练三：语法填空试题（共10空） 阅读下面短文，在空白处填入适当的情态动词或助动词，使短文语法正确、意义完整。 Last Sunday,I planned to meet Lily at the library,but she didn't arrive.I waited for an hour and then left. Later,I found out she was ill.She(1)have told me she was sick-I wouldn't have waited so long! Lily is always responsible,so I_(2)have guessed something was wrong.Her mother said she-(3) barely stand up that morning.She(4)have gone to the hospital,but she didn't want to miss our meeting. I feel bad now.I_(5)have called her to check if she was okay.Instead,I got angry.If I_(6)(know) she was ill.I would have visited her. Lily said,"You_(7)not blame yourself.I(8)have texted you,but my phone died.We laughed about it,but I learned a lesson:friends_(9)communicate more.Next time,I_(10)make sure to confirm plans in advance 参考答案 演练-：1B2.C3.A4.B5.C6B7.C8B9.C10.B 1.needn't leave 2.should have been 3.could have known 4.must have finished 5.mustn't park 6.could have gone 7.must be 8.should call 9.can't have seen 10.should have started 1.should have told 2.should have guessed 3.could barely 4.must have gone 5.should have called 6.had known 7.need not blame 8.should have texted 9.must communicate 10.will make 8