1、状语从句状语从句 （Adverbial Clause） 状语从句指句子用作状语时，起副词作用的句子。它可以修饰谓语、非谓语动词、定语、状语或整个句子。根据其作用可分为时间、地点、原因、条件、目的、结果、让步、方式和比较等从句。状语从句一般由连词(从属连词)引导，也可以由词组引起。（一）时间状语从句引导时间状语从句的连接词: when, as, while, whenever, after, before, till (until), since, once, by the time, every time1. as, when, while 的用法(1) 连接词 when 的用法小结a. “当
2、.的时候“, 引导的时间状语从句的谓语动词可以是延续性动词,也可以是短暂性动词,可用于主句和从句动作同时发生或从句动作先于主句动作.When the film ended, the people went back.When I lived there, I used to go to the seashore on Sundays.When you have finished your work, you may have a rest.b. “如果“,相当于 if.How can finish the job when he refuses to help me?When mixed wi
3、th water, the powder forms a smooth paste.c. 在那时，突然, 相当于 and at this / that time.常用于下列句型: (刚要.这时突然.)sb was doing sth when. sb was about to do sth when.sb was on the point of doing sth when. sb had just done sth when.2.连接词 while 的用法小结a.“当. 时候,和 .同时“, while 引导的时间状语从句中谓语动词必须是延续性动词或 be 动词Ill take care o
4、f your children while you are away.Strike while the iron is hot.b. “而,却“,做并列连词表对比. 侧重主句动作和从句动作相对比.（多放在句中）I like tea while she likes coffee.c. “尽管“, 相当于 although,(多放在句首)While I like the color of the hat, I do not like its shape.While I admit that there are problems, I dont agree that they cant be sol
5、ved.比较 when, while, as（1）动词 while 引导的时间状语从句的谓语动词必须是延续性动词或 be 动词，而 when引导的时间状语从句中谓语动词无论延续性动词还是短暂性动词皆可。When / While he was eating his breakfast, he heard the doorbell ring.When i stopped my car, a man came up to me.Strike while the iron is hot.2.顺序 从句动作发生在主句动作之前，只能用 when，不能用 as 或 while。When you have f
6、inished your work, you may have a rest.3 表示“随着，一边.一边，与.同时”，只能用 as，as 引导从句时侧重主从句同时或几乎同时发生或伴随进行，从句动作可以是延续性的，也可以是短暂性的.As the election approached, the violence got worse.4.“一. 就.“ 的表达法 :as soon as, the moment / minute / second / instant , immediately / directly / instantlyhardly/scarcelywhenno soonertha
7、nhardly / scarcely had sb done sth when sb did sth(前句常用过去完成式且为部分倒装形式,后句用过去式。)no sooner had sb done sth .than sb did sth5.until / till 的用法1.肯定形式表示的意动词必须是延续性的。否定形式,动词为非延续性也可以。肯定句：I slept until/till midnight.Wait till I call you. 等着我叫你。否定句：She didnt arrive until 6 oclock.Dont get off the bus until it h
8、as stopped. 公共汽车停稳后再下车。区别 2）until 可用于句首，而 till 通常不用于句首。注意：否定句可用另外两种句式表示。1）Not until在句首，主句用倒装 .Not until the early years of the 19th century did man know what heat is. 直到 19 世纪初，人类才知道热为何物。Not until I began to work did I realize how much time I had wasted. 直到工作，才认识到我已蹉跎了几多岁月。2）It is not until that 。例如
9、：It was not until I began to work that I realized how much time I had wasted.6.before 的用法(1) It will be / was + 时间段 +before(现在时) “还要过之后才”， It will be two years before he comes back.(2) It will not be / was not + 一段时间 + before(现在时) . 不多久就.It will not be a long time before he comes back.重点句型:(1) It wa
10、s + 时间点+ when“当时，时间是“It was 5 am when we arrived at the village.(2) It is / was at +时间点+ that. (强调句)It was at 5 am that they came back.注意:做此类题目关键要确定是不是强调句 ,当我们把 it, is / was 以及连接词去掉,剩余部分若能构成一个完整的句子，就是强调句,这时,连词用 that; 否则 ,就要考虑它的句式特点;（二）原因状语从句原因状语从句是表示原因或理由的，引导这类从句的最常用的连词是 because, since, as , now tha
11、t（既然 ), seeing (that), considering that, 等，because，as，since 与 for 的用法比较because：表示直接的原因或理由。用于回答 Why 的问题。because 与 so 不能同时并列使用。(前或后)since：表示对方已知的，无须加以说明的既成事实的理由。译为“既然”。(前)as：表示十分明显的众所周知的原因，一般说明因果关系。(后)for：常出现在并列句中，不说明主句行为发生的直接原因，只提供一些补充说明，且不可位于句首。(后)说明:上面说的“ 前“,指从句在主句之前; “ 后“,指从句在主句之后（三）地点状语从句where 引导
12、的定语从句与 where 引导的地点状语从句的区别(1) -Mom, what did your doctor say?-He advised me to live _ the air is fresher. (2006 四川)A. in where B. in which C. where 解析： 学生在做这个题目时脑海当中经常只记得 in which = where，其实这种结果的成立只存在与定语从句中解决这个问题，首先要区分清楚该句是什么从句，关系词前面并没有出现名词，也就是说没有先行词，那么该句就不可能是定语从句He lives where the rive lies.（live 后面
13、接了个地点状语从句）He lives in the quiet small village where / in which I worked ten years ago. （village 做先行词，后面接的是由 where 或 in which 引导的定语从句，在从句中做状语。 ）（四）目的状语从句引导目的状语从句最常用的词（组）是 that，so, so that（从句谓语常有情态动词，且不放在句首）, in order that,in case（以防，以免), for fear that, lest 等You must speak louder so that you can be h
14、eard by all. Marry spoke louder so that she was heard by all.注意：目的状语从句的谓语动词常和情态动词连用，否则可能是结果状语从句（五）结果状语从句结果状语从句是表示事态结果的从句，通常主句是原因，从句是结果。由 so that （从句谓语一般没有情态动词）, so that, such that 等引导。 e.g. She was ill, so that she didnt attend the meeting.a.比较 so.that.和 such . that 引导结果状语从句的区别 .TIPS:最好是搞清楚 so 和 suc
15、h 的词性,so 是程度副词,such 是形容词.词性的不同会影响到后面词语的顺序，现概括如下：so adj / adv that. (注意 such 就没有这种用法)so adj +a +单数名词 +that. so many / much/little/few +复数名词 / 不可数名词 +that.such +a / an +adj +n +thatsuch +adj + 复数名词/ 不可数名词 +that. 最好是能够记住以下几个短语：so nice a flower, such a nice flower, so many people, such nice flowers（六）条件
16、状语从句条件状语从句分真实性（有可能实现的事情）与非真实性（条件与事实相反或者在说话者看来不大可能实现的事情）条件句。引导条件状语从句的词（组）主要有 if, unless, so (as) long as, on condition that / if, so (as) far as, if only ( = if ), once, in case, provided / providing that 相当于 if, suppose / supposing that(假如)。 a.unless= if notb.区别 if only 过去:过去完成时; 将来:would / could /
17、might +情态动词+ 动词原形 或用一般过去时)He treats me so well as if I were his daughter.（九）比较状语从句比较状语从句常用 than, so (as) as, more / less.than., the more the more 等引导。比较状语从句既然是从句,that, as 之后一般是个句子,即有主谓成分,只不过有时谓语动作和前文所述一致,所以省略了，但是主语需用主格,虽然口语中偶尔有用宾格的情况. He is taller than me.（十）使用状语从句时要注意的几个问题a.在时间和条件（有时也在方式、让步等）从句中(即由
18、 when, while, if, unless, as, before, though, as, as though 等引导状语从句时) ，主句是一般将来时，从句通常用一般现在时表示将来。Well go outing if it doesnt rain tomorrow.Ill write to you as soon as I get to Shanghai.b.省略的情况1.有些时间、地点、条件、方式或让步从句，如果从句的主语与主句主语一致（或虽不一致，是 it） ，从句的谓语又包含动词 be ，就可省略从句中的“主语 + be”部分。When (he was) still a boy
19、of ten, he had to work day and night.2.在虚拟条件状语从句中，如果从句中有 had,should,were 时,可省略 if,用“had/should/were+sb“的结构 .If (you are) asked you may come in.If (it is) necessary Ill explain to you again.3.以 as, than 引导的比较状语从句可省略与主句中重复的成分以及 be 动词.She works harder than (she worked) before.c.注意区分不同从句：引导的是什么从句，不仅要根据连词，还要根据句子结构和句意来判别。以 where 为例，能引导多种从句。e.g. You are to find it where you left it.（地点状语从句）Tell me the address where he lives.（定语从句，句中有先行词）I dont know where he came from.（宾语从句）Where he has gone is not known yet.（主语从句）This place is where they once hid.（表语从句）
