1、原因状语从句引导原因状语从句的从属连词引导原因状语从句的从属连词 1、because 因为 表示造成某种情况的直接原因，回答why引导的问句，不能和so同时使用。I often exercise at the park because I love the clean air and sunshine.我经常在公园锻炼，因为我喜欢干净的空气和阳光。2、since既然 语气比because弱，表示对方已知或众所周知的原因。Since we have no idea about this problem,lets as Mr Wang for help.既然我们对这个问题不了解，就请王老师帮忙吧。
2、3、as 由于 语气比since弱，表示众所周知的原因，引导的从句可以放在主句前，也可以放在主句后。As it is getting late,I decide to leave now.由于天越来越晚，我决定现在离开。Since everyone is here,lets start Since so,I have nothing to say.Since you are wrong,you should say sorry.since侧重主句，意思是侧重主句，意思是“既然；由于；因既然；由于；因为为”，表示，表示已知的、显然的理由已知的、显然的理由since 比比as语气稍强，且比语气稍强
3、，且比as略微正式，它们引导的略微正式，它们引导的从句通常放在主句之前，有时也放在主句从句通常放在主句之前，有时也放在主句之后。不表示直接原因。之后。不表示直接原因。Since可用于省略可用于省略句，而其他连词不行。（见例句，而其他连词不行。（见例2）as 鉴于主从并重，从句说原因，主句说结果鉴于主从并重，从句说原因，主句说结果。As it is late,I must go.As you were not there,I left a message.as和和since的用法大体相同，表示附带说明的的用法大体相同，表示附带说明的“双方已知的原因双方已知的原因”或者理由不是很重要，但或者理由不
4、是很重要，但语气更弱，没有语气更弱，没有since正式，常译为正式，常译为“由于，由于，于于”。As it is raining,youd better take a taxi.既然在下雨，既然在下雨，你最好乘出租汽车。你最好乘出租汽车。As you are tired,you had better rest.既然累了，既然累了，你最好休息一下。你最好休息一下。1.Ill help you with your study _ you dont do well in it.A.so B.until C.since D.though2.-Could you tell me _ yesterday?
5、-Because my bike was broken on my way here.A.why you came late B.why do you come late C.why you come late D.why did you come late3._ you are wrong,you should say sorry to him.A.but B.Since C.until D.or4._the girl is 22,she takes care of her mother and cooks meals every day.A.If B.But C.Though D.As5.
6、_ she had no money to afford the expensive car,she had to give it up.A.So B.and C.Since D.UntilCABDCbecause of 也可表达直接的原因，只不过其也可表达直接的原因，只不过其接名词、代词或动名词。一般情况下可以接名词、代词或动名词。一般情况下可以because 引导的从句互换。引导的从句互换。1.由于生病，他不能来。由于生病，他不能来。He cant come _his illness.=He cant come _he is ill.2.由于大雨，他迟到了。由于大雨，他迟到了。He was
7、 late _getting up late.=He was late _ he got up late.because ofbecause because of because用用because连接下列句子连接下列句子1.He isnt at school.He is ill.2.The boys family is poor,his family cant afford his education.He isnt at school because he is ill.His family cant afford his education,because the boys family
8、is poor.3.Tom has seen the film several times.Tom wont go to see the film.4.Jackson was the King of pop.I love Jackson.Tom wont go to see the film because Tom has seen the film several times.I love Jackson because Jackson was the King of pop.用用as/since连接句子连接句子1.Im still alive.I must try to calm down
9、.2.Tan uses them a lot in his music.He likes the sounds of nature.3.Let me go instead.You are tired.4.Youll be punished.You often make mistakes.I must try to calm down since/as Im still alive.Tan uses them a lot in his music since/as he likes the sounds of nature.Let me go instead since/as you are t
10、ired.Youll be punished since/as you often make mistakes 1._(因为)you,he tries his best to work hard.2.Tony never spends money on books_ _ (因为)he doesnt like reading.3.-_ is the traffic so busy on the street?-Because they are waiting to watch the match.A Why B.Where C.How D.Who4.Why was he late for sch
11、ool?_ he got up too late.A.Since B.Because C、untilD、For5._ he exercises every day,_ he is very healthy.A.Because;so B.Though;but C.Because;/D.Though;/Because ofbecause ABc用用because,since/as 完成文章完成文章Our school give us free tickets to an opera it canhelp us learn more about different art forms.Millie
12、also planned to take the underground,we went to the theater together.When we arrived,it was still early,we went to buy some drinks.“Wed better be quick the opera will begin in 20 minutes.”Kitty suggested.We came back quickly.The bell was ringing,but Amy did not appear.After a while,we saw Amy runnin
13、g towards us.“Im late therewas too much traffic.She said out of breath.the opera had just started,we did not miss much.The opera lasted for 1.5 hours.We did not feel bored at all it was really wonderful.becauseSince/Assince/asbecausebecauseSince/AsSince/As1.选择填空。选择填空。1._ everyone is here,lets begin
14、our meeting.A.though B.so C.since D.or2._ he exercises every day,_ he is very healthy.A.Because;so B.Because;through C.Because;/D.Though;/3.The Australians are like the English in many ways _ they have manyBritish relatives.A.if B.because C.so D.although4.-Why was he late for school?-_he got up too late.A.Because B.Since C.As D.For5.-Is David at school today?-No,he is at home _he has a bad cold.A.because B.since C.as D.for6._ everybody knows about it,I dont want to talk any more.A.For B.Even C.Since D.Because7.I like Han Mei_ she is kind and helpful.A.so B.since C.because D.asAACC
