由as, (just) as…so…, as if, as though引导
1) as, (just) as…so…引导的方式状语从句通常位于主句后，但在(just) as…so…结构中位于句首，这时as从句带有比喻的含义，意思是"正如…"，"就像"，多用于正式文体，例如：
Always do to the others as you would be done by.
你希望人家怎样待你，你就要怎样待人。
As water is to fish, so air is to man.
我们离不开空气，犹如鱼儿离不开水。
Just as we sweep our rooms, so we should sweep backward ideas from our minds.
正如打扫房屋一样，我们也要扫除我们头脑中落后的东西。
2) as if, as though
两者的意义和用法相同，引出的状语从句谓语多用虚拟语气，表示与事实相反，有时也用陈述语气，表示所说情况是事实或实现的可能性较大。汉译常作"仿佛……似的"，"好像……似的"。这两个连词经常用在be，act，appear，behave，fell，look，seem，smell，sound，taste及其他描写行为举止的动词之后，引导一个方式从句。例如：
They completely ignore these facts as if (as though) they never existed.
他们完全忽略了这些事实，就仿佛它不存在似的。(与事实相反，谓语用虚拟语气。)
He looks as if (as though) he had been hit by lightning.
他那样子就像被雷击了似的。(与事实相反，谓语用虚拟语气。)
It looks as if the weather may pick up very soon.
看来天气很快就会好起来。(实现的可能性较大，谓语用陈述语气。)
说明：as if / as though也可以引导一个分词短语、不定式短语、形容词或介词短语，例如：
He stared at me as if seeing me for the first time.
他目不转睛地看着我，就像第一次看见我似的。
He cleared his throat as if to say something.
他清了清嗓子，像要说什么似的。
The waves dashed on the rocks as if in anger.
波涛冲击着岩石，好像很愤怒。
as if 和as though 引导的从句中的时态取决于说话者对所谈内容的态度。若说话者认为其看法是真的或可能会成为事实，从句谓语就按常规变化。
例如：
He looks as if he is angry.
他看上去好像生气了。
It looked as if there would be an exciting race.
看来要有一场激动人心的比赛。
When the spaceship leaves the earth at tremendous speed，the astronauts feel as if they are being crushed against the spaceship floor.
当宇宙飞船以巨大的速度离开地球时，宇航员们觉得自己好像正在被压向宇宙飞船的底壁上去。
如果从句的内容是不真实的，是与事实相反的，从句的谓语时态要用虚拟语气。主句谓语用一般现在时态，对从句的谓语形式没有影响。
例如：
He acted just as if he were afraid.
他装得好像很害怕的样子。
He behaves as if he were a child.
他的举止就像个孩子。[1]
其他的引导词
1)(in) the way (that)：Please pronounce the word the way I do.请照我这样,读这个单词.
2)口语常用的like：He sit there smiling like it was his birthday.他面带微笑坐在那儿,像是过生日似的. (这里用了虚拟语气，值得注意的是be动词用的was，而表示虚拟as if引导的be动词则只能是were。)
状语从句的简化
状语从句同时具备下列两个条件:①主句和从句的主语一致，或从句主语为it;②从句主要动词是be的某种形式。从句中的主语和be动词常可省略。例如：
When ( the museum is ) completed , the museum will be open to the public next year .
He’ll go to the seaside for his holiday if (it is ) possible.
3)固定句式：A is to B what C is to D 例如：
Nine is to three what three is to one.
另外，比较状语从句经常省略。例如：
I’m taller than he (is tall ).
The higher the temperature (is), the greater the pressure (is ).
就状语从句而言,有时为了使语言言简意赅,常常将状语从句进行"简化"。状语从句的"简化"现象在口语中较为普遍,而且在高考中的复现率也较高。因此,有必要对其进行全面、透彻的了解。
状语从句的"简化"现象常存在于以下五种状语从句中:①由if, unless等引导的条件状语从句;②由although, though, even if / though等引导的让步状语从句;③由when, while, as, before, after, until / till等引导的时间状语从句;④由as, as if等引导的方式状语从句;⑤由as, than等引导的比较状语从句。下面针对这五种情形作一归纳。
(1)当状语从句的主语是it,且谓语动词是be时,it和be要完全简化掉。例如:
If (it is) possible, he will help you out of the difficulty.如果可能的话,他会帮你摆脱困境。
You must attend the meeting unless (it is) inconvenient to you.除非情况对你来说不方便,否则你必须出席这次会议。
(2)当状语从句的主语和主句的主语一致时,从句可以将主语和be动词简化掉。常用于以下几种情形:
连词 形容词
As (he was) young, he learned how to ride a bike.他小时候就学会了骑自行车。
Whenever (she is) free, she often goes shopping.她有空就去逛商店。
Work hard when (you are) young, or you'll regret.少壮不努力,老大徒伤悲。[1]
连词 名词
While (he was) a young boy, he was always ready to help others.他在孩子时代就乐于助人。
Although (he was) a farmer, now he is a famous director.尽管他曾是个农民,但他已经是位著名的导演了。
连词 现在分词
As (she was) walking along the river bank, she was singing a pop song.她沿着河堤边走边唱着流行歌曲。
Although (he is) doing his best in maths these days, he has still got no good marks.尽管他一直在学数学,但他仍然没有取得好成绩。
连词 过去分词
He won't go there with us unless (he is) invited.除非受到邀请,否则他不会和我们一道去那里。
The concert was a great success than (it was) expected.这场音乐会出乎意料地取得了巨大成功。
连词 不定式
He stood up as if (he were) to say something.当时他站起来好像要说什么。
He wouldn't solve the problem even if (he were) to take charge.即使他来负责,他也解决不了这个问题。
连词 介词短语
She looked anxious as though (she was) in trouble.她看上去很焦急,好像遇到了麻烦。
He had mastered the English language before (he was) in the USA.他到美国之前就懂英语了。
解析：当从句主语和主句主语不一致时,从句部分要么用完全形式,要么用独立主格结构来表达，不能用其他形式表达。
When the meeting was over, all the people went out of the meeting-room.当会议结束时,人们都走出了会议室。=The meeting over,all the people went out of the meeting-room.
