8. ___ you understand this rule, you will have no further difficulty.

A. Before　　　 　　　　　　　 B. While　　　 　　 C. As　　　 　　　　　　　　 D. Once

7. The thief ran ____ he was out of sight in a short while.

A. so fast that　　 　　 B. too fast that　　 　　　 C. fast enough that 　　　 D. such fast that

6. Roses need special care _____ they can live through winter.

A. because　　 　　　　 B. so that 　　　　　 C. even if　　 　　　　　　 D. as

5. Mike acted ___ nothing had happened.

A. as　　　 　　　　　　 B. as though　　 　 C. as although　　　 　　 D. just like

4. I will let you drive ___ you have a driving licence.

A. unless　　 　　　　　 B. except　　 　　　 C. on condition that　 　 D. so that

3. ___ I admit that the problems are difficult, I don’t agree that they cannot be solved.

A. Since　　 　　　　　 B. As　　　 　　　　　 C. Even though　　 　　　 D. Because

2. Practise as ___ as you can.

A. much　　 　　　　　 B. many　　 　　　　 C. more　　 　 　　　　　　 D. hardly

例1、Generally speaking, _________ according to directions, the drug has no sid-effect.

A. when taking　　　 B. when taken　　　　 C. when to take　　　 D. when to be taken

答案为B。

[解析]　 这是一个由when引导的时间状语从句，原句应为“Generally speaking ,when it is taken according…”。由于take用被动时，主从句主语一致，因此从句中的it was可以被省略，简化为when taken…分词短语作状语，而选A、C时则缺乏主语。译文：通常地说，当这药按照指导说明被服用的话是没有副作用的。

例2、-Dad, I've finished my assignment.

-Good ,and _________ you play or watch TV ,you mustn't disturb me.　

A. whenever　　　 B. whether　　　　 C. whatever　　　 D. no matter

答案为B。

[解析]　 no matter不能直接引导让步状语从句，应用no matter + wh族疑问词方可，故排除D；尽管A、C都有“无论”的意思，但只有B项whether可与or连用，表示选择，即“无论你玩还是看电视，不许打扰我”。　

例3、The famous scientist grew up _______ he was born and in 1930 he came to Shanghai.

A. when　　　 B. whenever　　　 C. where　　　 D. wherever

答案为C。

[解析]　 where引导的是地点状语从句。译文：这位著名的科学家在他的出生地长大，1930年他来到上海。因为在从句中有表示时间的介词短语in 1930,所以可以排除when和whenever; wherever引导让步状语，意思是“无论在哪里”，与句意不符。

例4、________, I have never seen anyone who's as capable as John.

A. As long as I have traveled　　　 B. Now that I have traveled so much

C. Much as I have traveled　　　　 D. As I have traveled so much

答案为C。

[解析]　 这是一个让步状语从句。as在引导让步状语从句时，要把形容词或副词放在它的前面。如果是名词，一般不加冠词。如：Child as he is, he has learned two thousand new words .As long

　as“只要……”引导条件状语从句；Now that“既然”引导原因状语从句；As“因为”引导原因状语从句。译文：虽然我走过了那么多地方，我从来没有见过像约翰这样有能力的人。　

例5、In such dry weather, the flowers will have to be watered if they________.

A. have survived　 　B. are to survive　　 　C. would survive　　 D. will survive

答案为B。

[解析]　 这是一个条件状语从句，主句用了一般将来时态。在条件状语从句中，一般不能使用将来时，但能和be to do的形式连用，所以应填are to survive。译文：在如此干旱的天气里，如果你想要花成活，就得给它们浇水。

例6、The WTO cannot live up to its name _____ it does not include a country that is home to one fifth of mankind.

A．as long as　　　　 B．while　　　　 C．if　　　　 D．even though

答案选C。

[解析]　 从句子意思可知，是一个条件状语从句。as long as“只要……”引导条件状语从句经常用肯定句，所以要填if。译文：如果WTO不包括一个占人类五分之一的国家，它就名不符实了。

例7、She found her calculator　 ________ she lost it.

A. where　　　　　 B. when　　　　 C. in which　　　　 D. that

答案为A。

[解析]　 这是一个地点状语从句，意思是“东西是在丢的地方找到的。”in which用于定语从句中，其前必须有先行词。这个句子中没有先行词，所以不能填in which。　

例8、-I'm going to the post office.

- ________you're there, can you get me some stamps?

A. As　　 B. While　　 C. Because　　 D. If

答案为B。

[解析]　 while引导时间状语从句，意思是“当……时”。这句话的意思是“当你在那儿的时候，是否能给我买一些邮票？”as虽然也可以引导时间状语从句，但其意思是“一边……一边……”；because引导的是原因状语从句；if引导的是条件状语从句，对方已经说明要到邮局去，不能再作假设。

　例9、You should make it a rule to leave things ________you can find them again.

A. when　　　　 B. where　　　　 C. then　　　　 D. there

答案为B。

[解析]　 where引导地点状语从句。这句话的意思是“你应该作出一个规矩，把东西放在你能再找到它们的地方。”　

例10、We'll have to finish the job, ________.

A. long it takes however　　　　　　　 B. it takes however long

C. long however it takes　　　　　　　 D. however long it takes

答案选D。

[解析]　 however引导让步状语从句。要用陈述句的语序。

第三节 巩固练习

Direction: Beneath each of the following sentences there are four choices marked A, B, C and D. Choose the best answer that completes the sentence.

1. It is ___ he has behaved so badly that he must be punished.

A. as　　　 　　　　　　　 B. since　　 　　　　 C. because　　 　　　　　 D. that

5、as, though 引导的倒装句

as / though引导的让步从句必须把表语或状语提前(形容词、副词、分词、实义动词提前)。句首名词不能带任何冠词。

如句首是实义动词，助动词放在主语后。如果实义动词有宾语和状语，随实义动词一起放在主语之前。

例如：Child as /though he was, he knew what was the right thing to do.

= Though he was a small child, he knew what was the right thing to do.

Try hard as he will, he never seems able to do the work satisfactorily.

= Though he tries hard, he never seems…

虽然他尽了努力，但他的工作总做的不尽人意。

4、如从句表示"随时间推移"，连词能用as，不用when 或while。

例如：As the day went on, the weather got worse.　

日子一天天过去，天气越变越坏。