新外研版初中英语八下Unit4 语法专项 情态动词 课件

这是一份新外研版初中英语八下Unit4 语法专项 情态动词 课件，共33页。
教学课件外研英语八年级下册 Unit 4语法专项—— 情态动词语法 must/may/can 全解精讲+分层练习学习目标1.掌握三者表推测的用法及可能性差异2.理解表帮助意愿/责任的交际用法3.区分易混点，规避常见使用错误4.能在各类题型中灵活运用核心语法情态动词核心概念本单元核心：must/may/can两大核心功能功能一：表达对事情的推测与可能性功能二：传递帮助他人的意愿或责任通用规则：后接动词原形，无人称/数的变化日常交际高频考点，传递态度的核心语法表“推测”——must用法详解可能性强度：90% 极有可能，肯定推测用法场景：基于事实、逻辑或明显证据句式要求：仅用于肯定句，不可用于否定/疑问现在/将来结构：must + 动词原形/be例句：The box is heavy. He must need help.表“推测”——must的过去推测特殊规则：must表推测无单独过去式结构：must have + 动词过去分词适用：对过去发生的事做肯定推测例句1：You look tired. You must have worked late.例句2：He is late. He must have missed the bus.表“推测”——may用法详解可能性强度：50% 可能，不确定推测用法场景：无明确证据，仅表达合理猜测同义替换：might，可能性比may稍弱句式要求：可用于肯定句、否定句例句：It’s cloudy. It may rain later.表“推测”——may not的用法核心含义：may not = 可能不，表不确定否定结构：may not + 动词原形/be注意：无“禁止”含义，勿与mustn’t混淆例句：She’s busy. She may not come to the party.拓展：might not 用法与may not完全一致表“推测”——can’t用法详解可能性强度：0% 不可能，否定推测用法场景：基于事实，坚决否定可能性句式要求：仅用于否定句，can’t=cannot结构：can’t + 动词原形/be例句：His door is locked. He can’t be at home.表“推测”三者核心对比表“推测”使用技巧肯定推测：用must（强）/may（弱），不用can否定推测：不可能用can’t，可能不用may not无明确证据：优先用may/might表猜测有明显证据：用must（肯）/can’t（否）表判断例句：The light is off. He can’t be in the room.表“帮助的意愿/责任”——must用法核心含义：必须，强调责任、义务语气特点：语气强烈、坚定，不容置疑适用场景：道德、规则要求的帮助行为结构：must + 动词原形例句：We must help the old man cross the road.表“帮助的意愿/责任”——may用法核心含义：可以，表委婉请求/提供帮助语气特点：礼貌、委婉，正式交际常用适用场景：陌生人间/正式场合的请求/帮忙结构：May I + 动词原形（首字母大写）例句：May I carry the bag for you?表“帮助的意愿/责任”——can用法核心含义：能够/可以，表能力或主动帮助语气特点：自然、直接，口语化，日常最常用适用场景：熟人之间的主动帮忙或请求结构：can + 动词原形例句：I can help you with your homework.表“帮助”三者核心对比易混点辨析1——can的使用禁区can表推测时，绝对不能用于肯定句正确：He may be late for school.错误：He can be late for school.原因：can肯定句表能力/许可，不表推测表推测的肯定含义，需用may或must易混点辨析2——may not vs mustn’tmay not：表推测，可能不，无禁止含义mustn’t：表命令/禁止，不许、禁止，与推测无关正确：He may not come to the meeting.正确：You mustn’t play on the street.错误：You may not run in the hallways.易混点辨析3——must的双重含义表推测：肯定、一定，仅肯定句，有证据支撑例句：She must like painting. She draws every day.表责任：必须，肯定句，强调道德/规则义务例句：We must help each other at school.判断关键：结合语境看是否有推测依据易混点辨析4——can’t的双重含义表推测：不可能，基于事实否定可能性例句：It can’t be true. It’s too strange.表能力：不能、不会，侧重自身无能力做某事例句：I can’t swim. I never learned it.判断关键：语境是否存在否定推测的事实依据易混点辨析5——may和can的语气差异表主动帮助/请求时，二者均可使用can：更口语化、随意，适用于朋友/家人/同学may：更礼貌、正式，适用于陌生人/长辈/老师日常交流中，can的使用频率远高于may补充考点——needn’t的用法表达“不必做某事”，用needn’t，后接动词原形不可用must not表“不必”，二者语义完全不同must not：禁止做某事；needn’t：不必做某事例句：The deadline is tomorrow. You needn’t finish it now.语法拓展——推测类句式转换It’s possible that... → may + 动词原形I’m sure that... → must + 动词原形/beI’m certain that... → must + 动词原形/beIt’s impossible that... → can’t + 动词原形例句：It’s possible that it will snow. → It may snow.语法拓展——帮助/责任类句式转换have a duty to do... → must + 动词原形be able to do... → can + 动词原形Is it okay if I...? → May I...?例句：I am able to help you. → I can help you.综合练习1——用所给词填空1.You look pale. You ________ be ill. (must/may/can’t)2.He told me he’d stay home. He ________ be in the library.3.________ I borrow your pen? I need to write down the address.4.The cake is gone. Someone ________ have eaten it.5.It’s snowing heavily. We ________ not go out tonight.mustcan’tMaymustmay综合练习2——单项选择1.—Is that Lucy? —It ______ be her. She’s in London now.A. must B. may C. can’t2.We ______ help people in need—it’s the right thing to do.A. must B. may C. can3.The cat ______ be hiding under the bed—I heard a noise there.A. must B. may C. can’tCAA综合练习3——单项选择4.—______ I use your phone? —Sure, here you are.A. Must B. May C. Can’t5.I ______ help you move the desk—I’m strong enough.A. must B. may C. can6.It ______ be raining outside—the ground is dry.A. must B. may C. can’tBCC综合练习4——场景补全对话场景1：看到同学搬重物A: Look! He’s carrying so many books. It _________ be heavy for him.B: Let’s go and help. We _________ carry some for him.场景2：朋友感冒没来上课A: Is Tom absent today?B: He _________ have a cold—he was coughing yesterday.A: We _________ share our notes with him after class.mustcan must can综合练习5——改写句子1.It’s possible that she will come to the party. (用may改写)She ______ ______ to the party.2.I’m sure he is tired after running. (用must改写)He ______ ______ tired after running.3.It’s impossible for him to finish the task alone. (用can’t改写)He ______ ______ the task alone.may comemust becan’t finish综合练习6——改写句子4.We have a duty to help the poor. (用must改写)We ______ ______ the poor.5.Is it okay if I use your umbrella? (用may改写)______ I ______ your umbrella?6.I am able to help you with the project. (用can改写)I ______ ______ you with the project.must helpMay usecan help语法核心梳理——表推测must：90%肯定，仅肯定句，过去用must have+过去分词may/might：50%可能，肯/否定句，may not=可能不can’t：0%不可能，仅否定句，基于事实坚决否定核心原则：有证据用must/can’t，无证据用may/might语法核心梳理——表帮助/责任must：必须，表责任义务，语气强烈坚定may：可以，表委婉请求/帮忙，正式礼貌can：能够，表能力/意愿，口语化日常常用needn’t：不必，补充考点，对应must的“必须”语法核心梳理——易混点总结can表推测不用于肯定句，may not≠禁止mustn’t表禁止，needn’t表不必，二者不混淆must/can’t有双重含义，结合语境判断日常交际表帮助，熟人用can，陌生人用may语法核心梳理——通用规则所有用法中，must/may/can后均接动词原形三者均无人称和数的变化，主语单复通用表推测是本单元重点，表帮助是交际高频点句式转换是常考题型，牢记固定转换规则教学课件 Unit 4语法专项—— 情态动词语法 must/may/canThank you for listening!