1、状语从句一、概念：在复合句中充当主句状语的从句。二、状语从句的种类：1、时间状语从句，常由 after（在之后），as soon as（一就），before（在之前），since（自从），till/until（直到），when，while（当时候）等连词引导。I went to bed after the play was over yesterday.He will go home as soon as I come back.He didnt know any Chinese before he came here.It is twenty years since she joined t
2、he party.They worked till/until it was dark. When it rains，I go to school by bus.You must study hard while you are young.时间状语从句一般不用将来时， when、as soon as、till/until 引导时间状语从句用一般现在时代替一般将来时。来源:学优中考网 xyzkwwhen、as、while 都可表示“当时候”，但 when引导的时间状语从句动作和主句的动作可以是同时发生，也可以是先后发生，when 既可指时间点，也可指一段时间。用as、while 时则强调主句和
3、从句的动作同时发生， while 只能表示一段时间，从句须用延续性动词。As he walked，he sang happily. While I was reading，he came in.来源:xyzkw.Comtill 和 until都表示“直到为止”，主句用延续性动词，主句和从句都用肯定式。若表示“直到才”时，主句用终止性动词，从句用否定式，until 比 till 较正式，until引导的时间状语从句可以放在句首。Lets wait till the rain stops. She wont go away till you agree to help her. Until you
4、 told me，I had heard nothing of what happened.since 引导的时间状语从句，从句常用一般过去时，其主句一般使用现在完成时。2、条件状语从句，常由连词 if（如果）引导。（由 if引导的条件状语从句：主句用一般将来时，从句用一般现在时。）I will go shopping with you this evening if Im free.虚拟条件状语从句：主句用 would+动词原形，从句谓语动词用一般过去时。If I knew his telephone number，I would call him.3、原因状语从句，常由 as（由于），be
5、cause（因为），since（既然）等连词引导。来源:学优中考网As it was raining hard，they stayed at home.I didnt come here yesterday because I was ill. Since everybody is here，lets begin our meeting.来源:xyzkw.Com4、比较（或方式）状语从句，常由 asas（与一样），not as/soas（与不一样）than（比）等连词引导。She is as tall as her mother. I play football as well as John
6、. The earth is bigger than the moon.5、结果状语从句，常由连词 sothat（如此以致）suchthat引导。从句常用can、could 情态动词。 She was so tired that she couldnt eat supper.来源:学优中考网Its such an interesting story that everybody likes reading.6、让步状语从句，常由连词 though/although（虽然，不与 but连用）even though（即使）引导。 Although I am tired，I must go on working.He was happy though he was poor.7、目的状语从句，常由 so that（以便）引导，放在主句之后，从句中常有can、could、may、might 等动词。She bought a camera on line so that she can save a lot of time.学?优%中*考$，网
