复合句—状语从句
【复习目标】
▲掌握状语从句的作用。▲掌握状语从句的意义。▲掌握各种不同类型的状语从句。
【知识要点】状语从句在句中作状语，修饰句中的动词、形容词或副词等。
状语从句由从属连词作关联词，从属连词在从句中不充当句子成分。
状语从句在主句之前，一般要用逗号分开，朗读时用升调。
状语从句在主句之后，一般不用逗号，朗读时用降调。
状语从句按其意义和作用可分为时间、条件、原因、让步、目的、结果、方式、比较、地点等类型。
1. 时间状语从句
(1) 常用的连词有when（当……时候），while（当……时候）,before(在……以前)，after（在……以后），until(till)（直到……为止）,since（自从……以来）, as soon as（一……就）等。
(2) 时间状语从句中一般不用将来时，若谈论将来的事情，往往用一般现在时代替：
如：I'll go on with the work when I ________ (come) back tomorrow.
As soon as he ___________(finish) the work, he will come to see me..
2. 条件状语从句
常由if (假如、如果) No matter (不管) 来引导，如果主句是一般将来时，从句往往用一般现在时来表示将来。
如： I'll go for a picnic if it _____(be) fine.
No matter what he ________(say)，I won't believe him，
3. 原因状语从句
(1) 常由because, since, as引导。
(2) because表示直接的原因，着重点在从句，用于回答why, 语气最强。 because 不能与 so 连用。
since一般表示对方已知的，无须加以说明的既成事实的理由，全句中心在主句，语气比because弱，常译为“既然”。
as表示十分明显的原因，一般说明因果关系，着重点在主句，语气较弱。常译为“由于”。
for是个并列连词，只能放在另一个并列分句后面，表示一种推理或解释，或用作附加说明，而不是指理由或原因，语气最弱，一般不放在句首，常译成“因为”。
如：______ it is raining hard, we won't go hiking.
_______ you are ill, I'll go alone.
I can't go to school ________ I am ill.
You haven't met him, ______ he didn't come here.
4. 结果状语从句
一般由so...that, such...that引导，so 与such的区别： (1) so＋形容词＋a / an＋名词
(2) such＋a / an＋形容词＋名词 （3）such＋形容词＋不可数名词 / 可数名词复数
(4) so＋many / much / few / little＋形容词＋名词
如：It's _______ a heavy box that nobody can move it.
It's ______ heavy a box that nobody can move it.
There are _________many books in the library
5. 目的状语从句
往往由so that,引导，如：I'll speak slowly_________ you can understand me.
6. 比较状语从句
常由as...as, than, not as / so...as等引导。比较从句部分常是省略句，
如：I'm taller ______ he (is). Science is not _____ popular _____ English.
7. 让步状语从句
由though或although (虽然) 等引导，但不能与but同时连用，
改错：Though it snowed heavily,but they kept on working.
1. 方式状语从句
常用as if ,as though（好像）引导。如：He acted as if (though) nothing had happened.
2. 地点状语从句
常用where, wherever引导。如：I'll go where work is hard.
【典型例题解析】
例1 The question was _______ difficult that nobody could answer______.
A. very...them B. very...it C. so...them D. so...it
解析 因为句中有that,所以前面用so,构成so……that从句，而question是单数，用代词it，故选D。
例2 It was ______that he had to ask for help.
A. such big work B. so big a work C. so a big work D. such big job
解析 work是不可数名词，指工作或工程，故选A。
例3 He won't believe it ________ he sees it with his own eyes.
A. when B. after C. until D. as soon as
解析 此句是not……until,“直到……才”。故答案选C。
例4 I'll go _____ with you _______ next Sunday.
A. hunting...when I will have time B. to hunt...until I'm free
C. boating...if I have nothing to do D. to boat...as I will not be so busy
解析 去打猎、划船常用go hunting, go boating，所以应在A和C中选择，又因为when和if在句中引导状语从句时，要用一般现在时表示将来，故选C。
例5 It's almost three years _________ I last saw her.
A. since B. when C. that D. after
解析 本句表示自从上次见到她几乎有三年了，句型It's+时间段+since从句(过去时)，故选A。
【选讲例题】
用所给动词适当形式填空
例6 I'll go to Shanghai if I _______ (have) time tomorrow.
And I want to know if you ________ (have) time to go with me.
解析 第一句中if是“假如”的意思引导状语从句，要用一般现在时表示将来时，第二句中if是“是否”的意思，引导宾语从句，仍用将来时。
例7 —Could you tell me when he ________ (return) home next week?
—Sorry, I can't. But I will ring you up when he _________ (return) home.
解析 第一句中的when意思是“什么时候”，引导宾语从句用将来时态，第二句中的when是“当……时”的意思，引导时间状语从句，用一般现在时表示将来。
【课内追踪练习】单项选择
( ) 1.Jack was tired _______he played tennis all afternoon.
A. if B. as soon as C. because D. before
( ) 2____ he finished his work, he left hurriedly.
A. As soon as B. In order that C. Until D Since
( ) 3._____the rain has stopped, let's start again.
A. For B. Because C. Since D What
( ) 4.He started early ______ he could get there before n
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