1、语法复习专题（13）Unit13 状语从句%一、考点聚焦 1、时间状语从句 （1）as、when、while用法一览表。类别作 用例 句asas表示“当的时候”，往往和when/ while通用，但它着重强调主句与从句的动作或事情同时或几乎同时发生。She came up as I was cooking.(同时)The runners started as the gun went off.(几乎同时)when(at or during the time that )既可以表示在某一点的时候，又可表示在某一段时间内，主句与从句的动作或事情可以同时发生也可以先后发生。It was rainin
2、g when we arrived.(指时间点)When we were at school, we went to the library every day.(在一段时间内)whilewhile意思是“当的时候”或“在某一段时间里”。主句中的动作或事情在从句中的动作或事情的进展过程中发生，从句中的动词一般要用延续性动词。在when表示a period of time时，两者可以互换。Please dont talk so loud while others are working.He fell asleep while/when reading. Strike while the iro
3、n is hot.(用as或when不可，这里的while意思是“趁”)（2）引导时间状语从句的连接词除上述外还有：till, not until , until, before, sinceDont get off the bus until it has stopped.He waited for his father until(till)it was twelve oclock.It will be five years before he returns from England.hardly / scarcely when, no sooner than, as soon as o
4、nce表示“一就”As soon as I have finished it , Ill give yu a call.Once you show any fear, he will attack you.We had hardly got / Hardly had we got into the country when itbegan to rain.No sooner had he arrived / He had no sooner arrived than she started complaining.directly, immediately, the moment, the m
5、inute that 一就He made for the door directly he heard the knock.each time, every time, by the timeEach time he came to my city, he would call on me.注意：表示未来情况，主句用将来时，从句用现在时。2、让步状语从句（1）although与though可以引导让步状语从句，不能与but连用，但可以与yet连用。Although they are poor,(yet)they are warm-hearted.（2）even if或even though引导
6、让步状语从句，表示“即使”，“纵然”，用来使人注意下文所强调内容的性质。Ill get there even if(though)I have to sell my house to get enough money to go by air.（3）no matter后接上who、what、where、how等疑问词，也可以在这类疑问词后面加上ever构成whoever、whatever、wherever、however等。Dont trust him, no matter what / whatever he says.Whoever breaks the law will be publi
7、shed.No matter how hard the work is, youd better try to do it well.（4）as也可以引导让步状语从句。要用倒装。Child as(though)he is, he knows a lot.Much as I like it, I wont buy.Try as he would, he couldnt lift the heavy box.3、原因状语从句：because, for, as, since, now that（1）表示不知道的原因时用because,即说话人认为听话人不知道，因此because从句是全句最重要的部分
8、，通常它被置于主句之后。You want to know why Im leaving? Im leaving because Im full.for虽然表示不知道的原因，但其语气较because要弱得多，是可说可不说的话，它只能置于主句之后，这时，for是并列连词。如果不是因果关系，而是对前面主句的内容加以解释或推断时，只能用for。如：Its morning now, for the birds are singing.（很显然，鸟叫不可能是“现在已是早上”的原因。）（2）表示已经知道的原因时用as或since,即某种原因在说话人看来已经很明显，或已为听话人所熟悉，因此它是句中不很重要的部
9、分。since要比as正式一些，它们通常被置于语句之前，但有时却相反。Seeing all of the children already seated, he said,“Since everyone is here, lets start.”(3)下列情况下只能使用because:在回答why的问句时；在用于强调句型时；被not所否定时。4、地点状语从句：where, whereverMake a mark wherever you have any questions.We will go where the Party directs us.5、目的状语从句：that, so that
10、, in order that注意：目的状语从句的谓语动词常与情态动词连用，否则可能是结果状语从句。不可置于句首。6、结果状语从句：that, so that, so that, such that 注意：so + 形容词/副词 + that从句；such +名词 + that从句。7、方式状语从句：as, as if(though)Ill do as I am told to.It looks as if it is going to rain.8、比较状语从句：than, as9、条件状语从句：if, unless, so (as) long as, in case, once, a fa
11、r as, on condition that.注意if与unless的区别：不能用and连接两个unless从句，即不能有 unless ,and unless 。但if not and if not却不受此限。You wont lose your weight unless you eat less and unless you exercise more.()但可以说 unless you eat less and exercise more.10、注意状语从句中从句的省略现象（1）连接词 + 过去分词Dont speak until spoken to.Pressure can be
12、incrased when needed.Unless repaired, the washing machine is no use.（2）连词 +现在分词Look out while crossing the street.（3）连词 + 形容词/其他常见的有it necessary、if possible、when necessary、if any等。二、精典名题导解选择填空1. I dont think Ill need any money but Ill bring some _.(NMET 2000)A.as last B.in case C.once again D.in tim
13、e解析：答案为B。句意为“带些钱以防万一”，只能选择in case。引导的条件状语从句，后面省略了I should need it。2. The WTO cant live up to its name _ it doesnt include a country that is home to one fifth of mankind.（NMET 2000）A.as long as B.while C.if D.even though解析：答案为C。本题考查状语从句的用法。句意为“假如世贸组织不包括占世界人口五分之一的中国的话，那它就名不副实”。as long as语气过于强烈，while和e
14、ven though不符合句意。3、Someone called me up in the middle of the night, but they hung up_I could answer the phone.(NMET 2000)A.as B.since C.before D.until解析：答案为C。题意为：半夜里有人打来电话，我没来得及就挂了。but暗示在接话前就挂了。4.You should try to get a good nights sleep much work you have to do.A. however B. no matter C. although D. whatever解析：答案为A。此题考查连词用法，依据结构However +形/副+主语+谓语。故选A。5.He speaks English well indeed, but of course not a native speaker.A. as fluent as B. more fluent than C. so fluently as D. much fluently than解析：答案为C。此题考查So adj./adv. As和as adj. / adv. As 用法，前者主要用于否定句，在这里要修饰谓语动词，故选C。