Module4DiscoveryUnit7Theunknownworld第3課時Grammar語法聚焦原因狀語從句1.定義：在句中用來說明主句原因的句子叫原因狀語從句。2.常用引導詞:because(因為)，since(既然)，as(由于)，for(因為)3.時態(tài)：原因狀語從句一般都是根據實際情況選用適當的時態(tài)，通常是主過從過、主現從現。4.because,since,as和for的區(qū)別：(1)because引導的原因狀語從句一般放在主句的后面。當它位于句首時要用逗號與主句分開，放在句中時可不用逗號分開。because表示直接原因，語氣最強，適用于回答why引導的疑問句。注意：because和so不可同時出現在一個句子里。如：Wewentbybusbecauseitwascheaper.=Itwascheapersowewentbybus.我們乘公共汽車去，因為這樣便宜一些?！猈hydon’tyougoouttoplayfootballwithus?你為什么不和我們一起去外面踢足球？—BecauseIhavetolookaftermyyoungersisterathome.因為我得在家照顧我的妹妹。(2)since引導的原因狀語從句一般放在主句之前，表示已知的、顯然的理由(通常被翻譯成“既然”，相當于nowthat)，較為正式，語氣比because弱。如：Sinceyoudon’ttrusthim,youshouldnotemployhim.既然你不信任他，你就不該雇用他。Nowthatyouhavegrownup,youshouldnotrelyonyourparents.既然你長大了，就不該依靠你的父母。(3)as引導原因狀語從句時，表示附帶說明的雙方已知的原因，含有對比說明的意味，語氣比since弱，較為正式，位置較為靈活(常放在主句之前)。如：Asitisraining,you’dbettertakeataxi.由于正在下雨，你最好乘坐出租車。Iwenttobedearly,asIwasexhausted.我睡得早，因為我筋疲力盡了。(4)for引導的是并列句，表示上文未交代過的原因，但并不說明主句行為發(fā)生的直接原因，只提供一些附加或推斷的理由。for引導的并列句只能放在主句之后，并且必須用逗號將其與主句隔開。如：Hecouldnothaveseenme,forIwasnotthere.他不可能見過我，因為我不在那里。Heseldomgoesoutnow,forheisveryold.他現在很少出門了，因為他年事已高。5.because和becauseof的區(qū)別：(1)because是連詞，其后接原因狀語從句或回答以why開頭的特殊疑問句。(2)becauseof是復合介詞，其后接名詞、代詞或動名詞。如：Hedidn’tcomebecausehewasill.=Hedidn’tcomebecauseofhisillness.他因病沒來。課堂練習一、選用because，becauseof，since，as，for填空1.—Whyisheunhappy?—____________hefailedtheEnglishexam.2.____________everyoneishere,let’sbeginourdiscussion.3.____________thebadweather,theGreenshadtoputofftheirtravelplan.BecauseSinceBecauseof4.Weshouldbemorecareful,________itisalreadydark.5.________itwasapublicholiday,alltheshopswereshut.6.Hesoldhiscar________itwastoosmall.7.________youwon’thelpme,Imustdothejobbymyself.8.Hehadatrafficaccident__________hiscarelessness.9.Thisis________theEarthistravellingaroundtheSun.10.________Jimwasnotready,wewentwithouthim.forAsbecauseSincebecauseofbecauseAs二、選擇填空()1.—Whywereyoulateforschoolagain?(原創(chuàng)題)—_____Igotuplateandmissedthefirstschoolbus.A.Since B.Because C.As D.Becauseof()2.Allofushadtostayathome_____theCOVID-19duringlastSpringFestival.(原創(chuàng)題)A.becauseof B.as C.for D.sinceBA()3.—_____youarefreetoday,whynotseeamoviewithme?(原創(chuàng)題)—Soundsgreat!A.Since B.For C.As D.Becauseof()4.—_____itisraining,let’stakeataxitoschool.(原創(chuàng)題)—OK！A.Because B.For C.As D.BecauseofAC()5.MissLimustbeintheofficenow,_____thelightsinherofficeareon.(原創(chuàng)題)A.because

B.for

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D.sinceB三、語法填空

WewereonourwaybacktotheEarthfromanotherplanet.1._____________(sudden),aUFOappearedanditmadeourspaceshiplandonanotherplanet.Ontheplanet,averystrange-lookingalien2._______(meet)us.Hetookmyfriendsand3.______(my)toseehismaster.Thenwecametoaverystrangeroom.There4._________(be)manyaliensstandinginline.Allthealienshadfoureyes,twoheadsandsixlegs.TheyhadaSuddenlymetmewerewhitebodyandnohair.5.___________oursurprise,we6._____________(call)“aliens”bythem.Theplanetlookedlike7.___________prison(監(jiān)獄).Theygaveussomefood.Nooneatethefoodbecausewewere8.___________(frighten).Thenextday,theygaveusalonglistofthings9.___________(do),butwe