【新思路】人教版高中英语必修3课件：Unit 2 Healthy eating 5Grammar.ppt

人教课标高一必修3unit2 unit2healthyeating grammar findthesentencescontainingmodalverbsinthereadingpassage thenusuallybylunchtimetheywouldallbesold whatcouldhavehappened nothingcouldbebetter somethingterriblemusthavehappenedif hecouldnotbelievehiseyes perhapsheshouldgotothelibraryandfindout hehadbetterdosomeresearch eventhoughhercustomersmightgetthinaftereatingyonghui sfood theywouldbecometiredveryquickly a should oughtto都可表示 应该 oughtto用于表示按道理应当 常指客观的义务或责任 大多数情况下可用should代替 但比should语气重 ishouldhelpherbecausesheisintrouble yououghttotakecareofthebaby modalverbs b 表示劝告 建议或命令时 should和oughtto可通用 但在疑问句中常用should oughtto的否定式为oughtn tto或oughtnotto youshould oughttogotoclassrightaway shouldiopenthewindow whatshouldwedonext c should oughtto都可表示推测 heoughtto shouldbehomebynow thisiswheretheoiloughtto shouldbe 注意 should和oughtto后面跟动词不定式的完成式 其肯定句表示 过去应该做而未做 其否定句则表示 过去不该做但做了 youshould oughttohavemadethedecisionaweekago ishouldn thavemadesuchafoolishmistake 多数情况下 oughtto可与should互换使用 oughtto的反意疑问句用shouldn t替代 yououghttohavehelpedhimwithhisenglish a won tyoub oughtnotyouc shouldn tyoud wouldn tyou 2 must和havetomust的用法1 表示主观的义务和必要 主要用于肯定句和疑问句 意思为 必须 得 要 由must引起的疑问句 肯定回答要用must或haveto 否定回答要用needn t或don thaveto 意思是 不必 must的否定形式mustn t表示禁止 意思是 不能 不许 如 mustifinishthetaskrightnow 我现在必须完成这个工作吗 yes youmust yes youhaveto 是的 no youneedn t no youdon thaveto 不 不必 youmustn tcomeherewithoutpermission 未经允许 你不能来这儿 haveto的用法 1 must表示一种主观的需要 而haveto表示一种客观的需要 意思是 不得不 如 ihavetoattendanimportantmeetingthisafternoon 今天下午我不得不参加一个重要的会议 motherisout soihavetolookaftertheshop 妈妈不在家 因此我不得不照看商店 2 haveto的否定形式是don thaveto 相当于needn t 如 theydon thavetobuyacomputeratpresent 他们目前没有必要买电脑 thebosshasgiveneveryoneaspecialholiday sowe gotoworktomorrow a can tb mustn tc needn td shouldn t 点拨 考查情态动词 根据题意 可知这里表示 没有必要 故只能选c项 whatdoyouthinkwecandoforouragedparents you doanythingexcepttobewiththemandbeyourself a don thavetob oughtn ttoc mustn td can t 点拨 根据题意 除了和他们呆在一起做你自己外 没有必要做任何事情 可知这里选择don thaveto表示 不必 故选a项 3 must和needneed作情态动词时 只能用于疑问句和否定句 构成否定句和疑问句时不借助于助动词do needifinishtheworktoday yes youmust no youneedn t b must的肯定形式表示 必须 否定式表示 禁止 严禁 youmustcomehere youmustn ttakethebookawayfromthelibrary choosesuitablemodalverbsbelowtocompletethefollowingdialogues ought oughtn ttoshould shouldn twillmustn tneedn t don t havetocan can t 1 sam howcanigrowthinner mum mum well you eatfoodwithplentyoffibrethathelpsyoudigestbetter andyou stopdrinkingcolaoreatingsweetfood haveto should discoveringusefulstructures sam doesitmeani eatmyfavouritefriedchickenanymore mum notexactly ifyoulovefriedchicken you giveitup justeatitlessoften you worrytoomuch alittlefriedchicken doyougood shouldn t needn t don thaveto needn t shouldn t will 2 doctor youaresickbecauseyou veeatenpoisonousmushrooms wheredidyougetthem lucy ipickedthemintheforest iknowwe eatfreshvegetables doctor oh butyou eatthemuntilyou resuretheyarenotpoisonous lucy thankyou doctor i llbemorecarefulnexttime haveto mustn t 3 charles iwishicouldseethingsclearlyinthedark tom eatingcarrots helpyouseebetter you eatsomeeveryday oughtto should must oughtn tto don thaveto couldn t mustn t needn t can t haveto 用所给的情态动词填空 1 you goonworkingbecauseyoulooksotirednow 2 theweatherturnedouttobefineyesterday i havehadthetroubletocarrymyumbrellawithme oughtn tto don thaveto needn t 练习坊 must oughtn tto don thaveto couldn t mustn t needn t can t haveto 3 ifyouearnmorethan 5 000 you paytax 4 you playnow youshallfinishyourhomeworkfirst 5 iknowthingsarehardwithyou butyou trytogetoverthedifficulties haveto mustn t must haveto must oughtn tto don