第章状语从句学习指导状语从句在句子中作状语，用来修饰主句或主句的谓语。
一般可分为九大类,分别表示时间、地点、原因、目的、结果、条件、让步、比较和方式。
尽管种类较多,但由于状语从句与汉语结构和用法相似,所以理解和掌握它并不难。
状语从句的关键是要掌握引导不同状语从句的常用连接词。
现分别列举如下:状语从句分九类：在这一章节的学习中，要求同学们掌握各类状语从句基本概念，并能够灵活应用。
第一节时间状语从句时间状语从句用一般现在时表示将来。
连接时间状语从句的连接词有：2．when，while，as均可表示“当……的时候”。
when强调“特定时间”，表示主句谓语动词的动作与从句谓语动词的动作是同时发生的，或从句的动作发生在主句的动作之前；while表示的时间是一段，而不是一点，as多用在口语中，强调“同一时间”或“一前一后”，有时还有“随着”的含义。
When spring came, he felt like a trip.春天来了，他想去旅游。
As spring warms the good earth，all flowers begin to bloom．(as有“随着”的含义)as, when, while都表示主、从句的动作或状态同时发生，但三者也有区别。
as和when引导的从句既可表示一点时间，也可表示一段时间，从句中的谓语动词既可以是持续性动词，也可以为短暂性动词，经常可以互换使用；while引导的从句通常表示一段时间，从句中宜用持续性动词作谓语。
当从句中的谓语动词为持续性动词时，这三者可以通用（前面例句中已有体现），再如：1 / 18Mother was worried because little Alice was ill, especially as / when / whilefather was away in France.妈妈担心，因为小艾丽思病了，特别是当父亲远在法国的时候。
如果从句和主句要表示一个人的两个动作交替进行或同时完成时，则多用as，可译为“一边......，一边......”。
例如：He looked behind from to time as he went.他一边走，一边不时地往后看。
As time goes on, it's getting warmer and warmer..随着时间的推移，天气变得越来越暖了。
I thought of it just as you opened your mouth.你一张嘴我就知道你要说什么。
（若表示两个短促动作几乎同时发生时，用as的场合多于when.）当主从句之间表示转折或对比关系时，多用while, 不用as或when。
如：She thought I was talking about her daughter, while in fact, I was talking aboutmy daughter.她以为我在谈论她女儿，而事实上，我在谈论我的女儿。
如果表示从句的动作在主句的动作“之前”或“之后”发生时，多用when（=after）, 不用as或while。
此外，when还含有“at that moment”的意思（= andthen），引起的句子不能放在句首，也不能用as, while来替换。
例如：He was about to leave when the telephone rang.他正要离开，忽然电话铃响了。
We were watching TV when suddenly the lights went out.我们正在看电视，突然灯灭了。
They had just arrived home when it began to rain.他们刚到家，天就开始下雨了。
3．till／until，表示“一直到……”，主从句都用肯定式；表示“直到……才”，主句否定，从句肯定。
He worked until it was dark. 他一直工作到天黑。
2 / 18He did not get up till his mother came in. 一直到母亲进来他才起床。
4．once“一旦”，by the time“到……时”。
Once you see her, you will find what I said is true. 一旦你见到她就会发现我说的是对的。
by the time+现在时，主句用将来完成时。
By the time he arrives, we will already have left here. 等他到达时，我们将已离开这儿了。
by the time+一般过去时，主句用过去完成时。
By the time he arrived, we had already left here.他到达的时候我们早已离开这儿了。
5．as soon as，the moment表示从句动作一发生，主句动作随即发生，通常译为“一……就”。
As soon as I finish the work, I'll go to see you. 我一完成工作就会来看你。
She came to the scene the moment she heard the news.她一听到消息就来到现场。
6．since“自从”，before“在……前”，after“在……后”，It was not long before意为“不久”。
since引导从句用非延续性动词或“过去时间点”或“过去时间段+ago”，主句用完成时态。
Since he graduated, he has worked in this city. 他毕业后一直在这个城市工作。
I haven't seen him since last year/ three years ago. 去年以来/3年来，我没见过他。
选出最佳答案3 / 181) he was listening to the music, John fell asleep.A. AfterB. BeforeC. WhileD. As soon as-2) How did you try to get to school on time you missed the school bus.A. whenB. howC. whyD. that3) He was riding to school he was hit by a car this morning.A while B. when C. as D. so4) Lucy knew nothing about it her sister told her.A. becauseB. untilC. ifD. since5) The policeman asked the child cross the street the traffic lights turned green.A. not; whenB. don't; beforeC. not to; untilD. not to; since6) The book was so interesting that he had read it for three hourshe realized it.A. whenB. afterC. untilD. before7) we had seen all the animals, we went home.A. ThenB. AfterC. ThoughD. While8) She has made many friends she came to our school.A. beforeB. afterC. sinceD. until9) —How long has the weather been like this?A. Until last nightB. Ever since last nightC. Two days agoD. Two days later10) My uncle went to last year. We haven't seen him .4 / 18A. since almost a yearB. from almost a year onC. after almost a yearD. since almost a year agohe went to bed.11) He was so tired that he fell asleepA. as ifB. even thoughC. ever sinceD. as soon as12) I knew nothing about the accident my friend told me yesterday.A. becauseB. sinceC. untilD. after13) I didn't manage to do it you had explained how.A. untilB. sinceC. whileD. after【Keys】1) C 2) A 3) B 4) B 5) A 6) D 7)B 8) C 9) B 10) D 11) D 12) C13) A条件状语从句条件状语从句用一般现在时表示将来。
引导条件状语从句的连词有：if 如果；unless除非，如果不；on condition that条件是；as long as 只要2．表示正面的条件用if“如果”。
If you don't look after young trees, they will die very quickly.If the museum charges for entry, a lot of people won't be able to visit it. 3．表示否定的条件用unless( =if.．．not)“除非，如果不”。
I shall not go to the cinema unless I finish my homework before eight.说明：if…not常可以用unless替代。
If you don't study hard, you will fail in the exam.You will fail in the exam unless you study hard.5 / 184．表示使某事成为现实必要的条件用on condition that“条件是”，as long as‘‘只要”。