九年级英语 Unit 4 Inventions and Inventors课件北师大版.ppt

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1、Unit4InventionsandInventors一、本周教学重点：1.复习被动语态2.情态动词表达怀疑、确定和可能。3.重点词汇二、具体内容：（一）被动语态：1.一般现在时被动语态基本结构：主语＋am/is/are＋过去分词Thefoodisplacedintheoven.Theyareturnedintoheat.2.一般过去时被动语态基本结构：主语＋was/were＋过去分词MagicSquareswereinventedinChina.PapermakingwasintroducedintoJapanin610.3.情态动词被动语态基本结构：主语

2、＋can/should/must＋be＋过去分词Schooluniformmustbewornatalltimes.4.一般将来时被动语态基本结构：主语＋will＋be＋过去分词Itcan’tbearadiobecauseit’stoobigtobearadio.Thereportwill______（finish）intwodays’time.Milkshould_______（keep）inthefridge.Whiteclothesandcoloredclothesshouldnot_______（wash）together.Schooluniform

3、sneedn’t______（wear）atalltimes.（二）情态动词：当不是很确定时，用might或may.（might比may更不确定）Whoknowswhatwillhappen.Youmayevenhavemarriedbythen.Itmightbeatoolforcuttingthings.Idon’tknow.当确定某件事是唯一的可能时，用must.Itmustbesomesortoftoy.当确信不可能发生时，用cannot.Itcannotbearadiobecauseit’stoobigtobearadio.Ex.Completet

4、hesentenceswithmightbe/maybe,cannotbe,ormustbe.1.Thisexam_________toodifficultforthestudents.Idon’tthinktheycanfinishit.2.It_________abookforchildren.Therearemanycartoonsinit.3.It_________true.Ithinkyoumadeamistake.4.Mr.Smith________________inLondon,Paris,orTokyo.Nooneknowsforsure.

5、5.That_________John.HeisinNewYorknow.6.Didyouhearthedoorbell?It_______Nicholas.Iamexpectinghim.（三）重点词汇：1.Inmanybigcitiesintheworld,theoveruseofcarsisthoughttobeoneofthemajorcausesofairpollution.over＋名词/形容词，表示“过多，过于”Theover-loadtruckcausedaseriousroadaccident.Shealwaysworksovertime,

6、soshehastoleaveherbabycaredforbyhermother.bethoughttobe被认为，被看作Sheisthoughttobethetopstudentinourclass.Janeisthoughttobebusypreparingfortheexam.2.Howeverwearealsowarnednottoaskforprettycolors,becausethecarwillcomeingrayonly.warnNoonewarnedhimofthedanger.Iwarnedhernottogetclosetothed

7、ogbutshewouldn’thearofit.3.Otherexpertsaresurethatthefuturewillbehappy.besurethat…Iamsurethatsmokingwillhurtyou.AreyousurethatJohnwillcomethisafternoon?4.Ifgasisinshortsupply,thesupercarwillrunonwater.beinshort…Thecheaperitis,thebetter.I’mshortofmoney.on靠Hefindsitdifficulttoliveonh

8、issalary.Theylivemostlyonv