原因状语从句

原因状语从句because,since,as,for,这几个词都是表示“原因”的连词，语气由强至弱依次为：because＞since＞as＞for

其中because,since,as均为从属连词，引导原因状语从句；而for是并列连词，引导并列句。

1.because表示直接原因，其语气最强。常用来回答why的提问Istayedathomebecauseitrained.—Whyissheabsent?

—Becausesheissick.

在强调句型中，只能用becauseItwasbecauseImissedtheearlybusthatIwaslateforschool.要点：不要把连接词because与介词短语becauseof(+名词或-ing形式)相混淆；Helayinbedbecausehehadcaughtabadcold.

Helayinbedbecauseofabadcold.since表示显然的或已为人所知的理由，

常译为“因为”、“既然”，通常置于句首，表示一种含有勉强语气的原因。Sinceheasksyou,you'lltellhimwhy.

Sinceeveryoneishere,let'sstart.as含义与since相同，但语气更弱，没有since正式Wealllikeherassheiskind.

AsIhadacold,Iwasabsentfromschool.

for表明附加或推断的理由,它所引导的分句只能放在句子后部,并且前后两个分句间的逻辑关系不一定是因果关系,其间用逗号隔开.Thedaysareshort,foritisnowDecember.Itmusthaverained,forthegroundiswet.nowthat既然.常放句首.Nowthatyouhaveleftuniversity,youwillhavetofindajob.Nowthateverybodyishere,let'sbeginthediscussion.1.Don’tbeafraidofaskingforhelp____itisneeded.A.unlessB.sinceC.althoughD.when2.Marywasmakingadress___shecutherfinger.A.whenB.whileC.asD.after3.Itwas_____backhomeafterexperiment.A.notuntilmidnightdidhegoB.untilmidnightthathedidnotgoC.notuntilmidnightthathewentD.untilmidnightwhenhedidnotgo4.UnlikewatchingTV,readingisahighlyactiveprogress(过程),___itrequiresattentionaswellasmemoryandimagination.A.untilB.butC.unlessD.for5.ShethoughtIwastalkingaboutherdaughter,___,infact,Iwastalkingaboutmydaughter.A.whomB.whereC.whichD.while6.____quiterecently,mostmothersinBritaindidnottakepaidworkoutsidethehome.BeforeB.UntilC.FromD.Since7.____youareleavingtomorrow,wecaneatdinnertogethertonight.ForB.SinceC.BeforeD.While

8.MrBrownreturnedhomejust___hisfamilywerehavingsupper.AthenBasCwhenDwhile9._______hetookpartinthecompetition,hewonasecondprize.AThefirsttimeBForthefirsttimeCAtthefirsttimebecause1.语气强，可放在主句前或后，表示直接因果关系，回答why提出的疑问句，用在强调句式结构中。汉语中的：“因为-----所以------”在英语中的表达只能使用because或so中的一个，不能同时使用这两个单词。1.那个男孩因病缺席。

Theboywasabsentbecausehewasill.Itwasbecausehewasillthattheboywasabsent.

2.-----Whycan'tyougotherenow?------_____I’mtoobusy.3.(Trueorfalse)BecuseIhadnothingbettertodo,soIdecidedtogotoWufengMountainwiththem.

because要点：不要把连接词because与介词短语becauseof(+名词或-ing形式)相混淆；Helayinbedbecausehehadcaughtabadcold.Helayinbedbecauseofabadcold.1.Tomwaslateforschool.That’s_____hegotuptoolate.2.Tomgotuptoolate.That’s_____hewaslateforschool.thisis/thatis/itisbecause后面接原因。thisis/thatis/itiswhy后面接结果-----WhoknowswhereTerryis?-----Thereason_____Terryisabsentis______hisfatherhadanaccident.

Awhy;becauseBwhy;thatCthat;becauseDthat;/as表示十分明显的原因，一般说明因果关系，着重点在主句，语气比because弱，常译为“由于”。as引导的从句可放在句首或句末。1.由于正在下雪，我们不去公园了。Asitissnowing,weshallnotgotothepark.2.由于我没有读过这本书，所以我无法告诉你有关它的事情。

AsIhavenotreadthebook,Icannottellyouanythingaboutit.1.(2012重庆)------Coach,canIcontinuewiththetraining?-------Sorry,youcan’t______youhaven’trecoveredfromthekneeinjury.

AuntilBbeforeCasDunless2.Do______youaretoldto,oryou’llbefired.AasBwhileCbeforeDsince3.________thedaygoeson,theweatherisgettingcolderandcolder.AWithBSinceCWhileDAs变成with的复合结构

Withthedaygoingon

3.since一般表示对方已知的，无需加以说明的既成事实的理由，全句中心在主句，语气比because和as弱，常译为“既然”。now(that)与since意思接近，表示“既然，鉴于”。表示一种含有勉强语气的原因。since和nowthat引导的从句常放在句首。1.既然你要去，我也要去。Sinceyouaregoing,Iwillgo.2.Sinceyouaregrownup,youshouldnotrelyonyourparents.1.(2005北京)Itisalmostfiveyears______wesaweachotherlasttime.

AbeforeBsinceCafterDwhen2.(2011四川)Asisreported,itis100years______QinghuaUniversitywasfounded.(whenbefore,after,since)

3.-----Howlongisit_____hearrivedhere?------Abouthalfanhour,Isuppose.AsinceBbeforeCwhenDafter1.(NMET1999)_______you’vegotachance,youmightaswellmakefulluseofit.

ANowthatBAfterCAlthoughDAssoonas2.____noonehasreadthebook,wecan'tdiscussit.3.____therainhasstopped,let'sgohomeatonce.(since,nowthat)A

Since

Nowthat1.既然雨已停了，让我们立刻回家吧。

Nowthattherainhasstopped,let'sgohomeatonce.2.既然没有人读过这本书，我们就不能对它进行讨论。

Sincenoonehasreadthebook,wecan'tdiscussit.for意思是“因为”，但它不是从属连词，而是并列连词，是用来说明，补充解释或表示一种推理，它所引导的分句只能放在句子后部,并且前后两个分句间的逻辑关系不一定是因果关系,其间用逗号隔开.1.我们得早点出发，因为我们有很长一段路要走。Wemuststartearly,forwehavealongwaytogo.Itmusthaverainedlastnight,forthegroundiswet.1.(2008山东)Hefounditincreasinglydifficulttoread,_______hiseyesightwasbeginningtofail.

AthoughBforCbutDso2.（2006湖南）Amancannotsmilelikeachild,_______achildsmileswithhiseyes,whileamansmileswithhislipsalone.

AsoBbutCandDfor1._____(Because,For,As,Since)hermotherwasill,thegirlhadtostayathometolookafterher.2.Iamsoglad,______(for,as,since,nowthat)thebirdissinginganditissunny.3._____(Since,Before,As,When)timewenton,Einstein'stheoryprovedcorrect.1.(2010辽宁)The