Unit 5 The Value of Money Discovering Useful Structures(课件)高一英语(人教版2019必修第三册）.pptx

Unit5TheValueofMoneyDiscoveringUsefulStructuresP54

Modalverbs情态动词

Leading-inMayweaskwhatyouredoinginthiscountryandwhatyourplansare?IcantsaythatIhaveanyplans.Youmustntworryaboutthat.Couldyouoffermeworkhere?Readthesentencesbelowandthinkabout:Whatarethefunctionsandmeaningsofthesemodalverbs?A.necessityB.possibilityC.obligationD.requestE.adviceF.intention

一、情态动词的特征情态动词有一定的意义，表示或暗示某种情绪或态度，表示可能、建议、愿望、必要、允许、能力等。大多数情态动词有多个意义。2.情态动词没有人称和数的变化，即不随主语的不同而变化。3.情态动词不能独立使用，须后接动词原形，一起构成谓语动词。4.情态动词除ought和have外，后面接不带to的不定式。(dare)5.情态动词没有非谓语形式，即没有不定式、分词等形式。

1.只作情态动词的：2.可情态可实义的：3.可情态可助动词的:4.相当于情态动词的:二、情态动词的分类can/could,may/might,oughtto,mustneed,dareshall/should,will/wouldhaveto,usedto

ExampleNecessityPossibilitiesObligationRequestAdviceIntentionWecandiscussitnow.Youmustdoitatonce.Wouldyoupleasepassmethesalt?Youneedn’thavestayed.Yououghttohelphim.Iwouldratherdoitmyself.

cancould情态动词的用法(1)表能力，“能，会”ShecanspeakEnglish.Shecouldplaythepianoattheageofthree.beableto能用于各种时态；can/could只能表示现在或过去的能力。was/wereableto“设法做成某事”相当于managedtodosth//succeededindoingsthAllthepeopletrappedintheburninghousewereabletogetoutofit.

(2)表请求和许可，“可以”，could比can更加委婉，表示礼貌CanIsmokehere?—CouldIuseyourcomputer?—Yes,youcan.(3)can表客观可能性，“有时候会”，用于肯定句Awisemancansometimesmakeamistake.(4)can表推测，用于疑问句、否定句。肯定句用mustCanthenewsbetrue?Hecan’tbeathomebecauseIsawhimherejustnow.

can/could与beableto的区别1.Themancan/couldspeaktwoforeignlanguages.2.YesterdayIwasabletogethomebeforetheheavyrain.can/could表示_________________，而beableto通常表示通过努力达成的_____________;can/could主要是一般现在、一般过去时,而beableto有较为丰富的时态变化。习惯性具备的能力一次性的能力

may和mightMayIhavealookatyourbook?Youmayusemaydictionarysolongasyoureturnitbefore7:00.Hemaybewaitingforyouatthestation.Theymayhavegotlost.可能性许可请求may/mighthavedone过去的猜测当