状语从句的省略（结合分词学习笔记：分词短语作状语时可以保留相应的连词）
同时满足以下两点：
1.主句的主语和从句的主语一致，或从句主语是it;
2.从句谓语中含有be动词的情况下，可以将从句的主语和be动词省去。常用于时间、地点、条件及让步状语从句中。
- 时间状语从句的省略
Metal expand when heated and contract when cooled.金属具有热胀冷缩的特性。
Metal expand when they are heated and contract when they are cooled. - 条件状语从句的省略
A tiger can't be tamed unless caught very young.老虎只有在年幼时捉来才能被驯服。
A tiger can't be tamed unless it is caught very young. - 让步状语从句的省略
Although not an economist himself,Dr. Smith has long been a severe critic of the government's economic policies.尽管史密斯博士本人不是经济学家，但他一直以来对政府的经济政策提出尖锐的批评。
Although he is not an economist himself,Dr. Smith has long been a severe critic of the government's economic policies.
时间状语从句
时间状语从句就是用来说明主句动作与从句动作发生时间上的先后关系，时间状语从句所表达的时间概念不外乎三种：过去、现在和将来。
学习时间状语从句要牢牢把握两个核心要点：
- 注意主句、从句的时态搭配关系。不同时间从句的连词，这种搭配关系是不同的。
- 注意主句、从句的谓语动词的待续性和短暂性。
时态搭配关系不同，句子的意思就有可能不同，这是学习时间从句的难点。
时间连词when的用法特点
表示过去:
- 主句一般过去时 + 从句一般过去时
I started my dinner when he left.他走之后，我才开始吃晚饭。（表示从句动作先发生） - 主句一般过去时 + 从句过去完成时
I started my dinner when he had left.
以上两种意思上面区别不大。对于某些句子来说，还是有区别的：表示两个相继发生的动作时，用过去完成时可以表示一个动作完成以后，另一个动作才开始发生，从而使得两个动作相互独立，彼此脱离开来。一般过去时，则可能表示一个动作“导致”另一个动作的发生，或两个动作之间有一种因果关系。例：
When I had written my letters I did some gardening.我把信写完后，就到花园里干了些话。
When I wrote him a letter, he came at once.我给他去了封信后，他立即就来了。 - 主句过去完成时 + 从句一般过去时
表示主句动作先发生，则主句须用过去完成时。
I had started my dinner when he left.他走的时候，我已经开始吃晚饭了。 - 主句一般过去时 + 从句过去进行时
The doorbell rang when I was telephoning.门铃响的时候我正在打电话。(具体看状语从句学习笔记1) - 主句过去进行时 + 从句一般过去时
I was telephoning when the doorbell rang.我当时正在打电话，突然门铃响了。(具体看状语从句学习笔记1)
表示将来：
- 主句一般将来时 + 从句一般现在时
表示将来动作时，主句用一般将来时，从句用一般现在时表示将来，不能使用将来时态。
I'll speak to him when he arrives.他来了以后我会和他谈谈。 - 主句一般将来时 + 从句现在完成时
从句中用完成时态是为了强调：在从句结束了之后，主句动作才开始发生，此时从句的动作一般都需要持续一段时间。
I'll go when I have had my dinner.我吃完饭就去。
I'll give you a call when I have finished the work.工作做完后，我就给你打电话。（第六、七两组时态的差别类似于第一、二两组时态差别） - 主句将来完时 + 从句一般将来时
将来的动作中，表示主句动作先发生，则主句要用将来完成时，从句用一般将来时
The performer will already have played the music when we get there.一会我们到的时候，那位演奏家一定已经弹完那首曲子了。 - 主句将来进行时 + 从句一般现在时
与第四、五组“进行时与一般时”的搭配类似。
The performer will be playing the music when we get there.一会儿们到的时候，那位演奏家一定正在弹那首曲子。
表示一般现在动作：
- 主从句都用一般现在时态
表示一般动作的when引导的从句往往是说明一般情况，阐明一个道理，因而常出现在名言警句、谚语或格言中。
whenever引导时间状语从句
表示“无论何时”，它相当于when的强调形式。
Whenever someone asks you something you don't want to answer,smile and ask,"Why do you want to know?"当别人问你什么问题而你不想回答时，笑着说：“你为什么想知道这个？”
时间连词while的用法特点
意思相当于during that time(在...期间)，表示某一时间段内发生的动作。因此从句谓语动词通常接延续动词。
The phone rang while I was taking my bath.电话铃响的时候我正在洗澡。
You wait here while I go and get it.你在这里等着，我自己去捡。（go and get尽管是短暂动词，但两动词连用表示一段时间内的活动，所以用while）
while除了表示时间外，还可以表示另外三种意思：表示条件的“只要”、表示对比的“然而”、表示让步的“尽管”。
时间连接as的用法特点
as引导时间从句时，相当于while，从句接延续动词。主句的谓语可以是延续动词，也可以是短暂动词。一般译成“正当...”,"随着...","一边...一边..."
The arrow fell into the river as the boat was drifting on the water. The soldier tried to retrieve it.船在水面上行驶时，箭突然掉进了河里。这名士兵想找回这支箭。
时间连词before的用法特点
与when一样，主从句会有各种时态搭配关系，较常见的是“主句用过去完成时，从句用一般过去时”。作者没有讨论其它的时态搭配。
时间连词after用法特点
主从句也有种时态搭配关系，作者没有详细讨论。
时间连词since用法特点
since时间连词特殊用法
since作为时间连词与现在完成时密切相关
一般句型为：
since后面接从句谓语一般过去时，主句谓语则用现在完成时态
- since + 短暂动词
since子句 + 一般过去时（现在完成时）按句面意思翻译既：从句动作“结束”以来，主句活动在持续
例：
I have worked in this company since I left school
I have worded in this company since I have left school
意思一样：我来中国已经有三年了 - since + 延续动词
since子句 + 一般过去时态 ：从句动作“结束”以来，主句活动在持续
since子句 + 现在完成时态 ：从句动作“开始”以来，主句活动在待续
例：
It's been three years since I worked in this company
It's been three years since I have worked in this company
我不在这家公司工作有三年了
我在这家公司工作有三年了
时间连词until的用法特点
until表示“一直到” 2. not...until表示"直到...才..."
until用法三个要点：
- 既可以用作介词也可以作连词，所以until后面可以接名词短语也可以接时间从句。
- until本质是表示“一个主句动作一直持续到某一个时间点”。具体来说就是：until前面的主句或句子谓语必须是待续性的，而until后面接的从句谓语须是短暂动词或接时间点。
- 作为连词引导从句时的句型：主句的延续动词 + until + 从句的短暂动词
作为介词接名词短语的句型：延续动词 + until + 时间点（不是时间段，表示时间点的名词短语）
用法特点：
- 延续动词 + until + 短暂动词或时间点
Wait until he comes back 等他回来吧。
Until I came back,he was waiting for me at my home.在我回来之前，他一直在我家里等我。
I will be away from my office until next Tuesday.我将要离开办公室，要到下周二才能回来。（时间点） - 短暂动词 + until + 短暂动词或时间点
主句谓语是短暂动词时，要用否定形式，因为否定之后表示是一个状态，状态就是延续。not...until(直到...才...)
He didn't leave the office until his boss came back.直到老板回来后，他才离开办公室。
Ice cream did not reach America until about the middle of the eighteenth century.直到18世纪中叶，冰淇淋才传到美洲。 - not...until的四种句型结构，以下四种结构核心意思相同
- 结构一：正常结构
即最常见的结构not...until。
The little boy didn't smile until he saw his mother.这个小男孩看到他妈妈之后才开始笑起来。 - 结构二：until置于句首
由结构一演变过来，until...,not,这种结构上的移位，在翻译时很容易被我们误解。
Until he saw his mother,the little boy didn't smile. - 结构三：倒装结构
由结构二变化过来，not until...,谓语助动词 + 主语 + 谓语动词。此时主句采用部分倒装结构。
Not until he saw his mother,did the little boy smile. - 结构四：强调结构
由结构三变化过来，It was not until + 时间从句或短语 + that + 主句部分。
It was not until he saw his mother that the little boy smiled.
- 结构一：正常结构
表示“一...就...”的结构
表达主句动作和从句动作相继发生，两者发生时间间隔不长，此时主句和从句的谓语都是短暂动词。
从句动作先于主句动作
关系连词有：as soon as,once,the minute,the moment,the instant,immediately,directly,instantly等，这些连词用法句式结构是一样的，主从句时态一般一致，比如表示将来，主句用一般将来时，从句用一般现在时来表示。
We will leave as soon as it stops raining.雨一停，我们就动身。
表示过去的动作，则主句和从句都用一般过去时。
It began to rain as soon as I arrived home.我刚到家，天就开始下起雨来。
as soon as可换成其他连词，比如immediately,instantly,directly.
It began to rain immediately I arrived home.
或者换成带定冠词the的连词，比如the moment,the minute,the instant.
Don't trust those who leave their friends the moment they get into difficulty!一旦朋友陷入困境就会转身脱逃的人，我们不能信任。-
主句动作先于从句动作发生
连词有：hardly...when,scarcely...when,no sooner...than.这些连词用法和句式结构都不相同，主从句时态一般也不一致。多用于表示过去的动作，主句多用过去完成时，且常倒装，从句用一般过去时。可与as soon as等从句、方句互换。
No sooner had I arrived home than it began to rain.(than后面it began to rain是从句，主句为had I arrive home)
It began to rain as soon as I arrived home.Hardly had I arrived home when it began to rain.
Scarcely had I started to type my paper when the telephone rang.
时间连词by the time用法特点
by the time是一个介词短语，起着连词的作用，其后可以直接加一个从句，表示“在...之前”强调“一个动作在另一个动作发生之前已经完成”。因此by the time主句要用完成时态。
- 表示过去的动作：主句用had done + by the time +从句用一般过去时态
We had already left by the time they arrived.那天他们到的时候，我们已经先走了。 - 表示将来的动作：主句用will have done + by the time + 从句用一般现在时态
We will have already left by the time they arrive.一会等他们来的时候，我们就将离开了。
一些表示时间的名词短语引导的时间状语从句
名词短语可当作连词，常见有：next time,every time,each time,the day,the week等。
地点状语从句
结构where + 陈述句，可以在句首或句末。
A driver should slow down where there are schools.
放在句首，翻译时往往失去“地点”的含义，要灵活处理。
Where there is Love,there is also Wealth and Success!只要有爱，就会有成功和财富。
另外了也可由wherever,anywhere,everywhere引导状语从句。
Wherever he happens to be,Clint can make himself at home.无论在什么地方，克林特总是无拘换束。
He would live with his grandmother anywhere she lived.不管他祖母住在哪儿，他都愿和她住在一块儿。
原因状语从句
常用连词：because,for,as,since.
because语气在四个连词中连词最强，只有它才能回答why提问，引出的原因往往听话人所不知道的或最感兴趣的，也只有because才能被如only,just,perhaps等来修饰。
My friends dislike me because I'm handsome and successful.我的哥们都不喜欢我，因为我长相英俊又事业有成。（听者感兴趣的原因）since表示人们已知的事实或不需强调的原因，常译成“既然”
Since we don't have class tomorrow,why not go out for a picnic?既然明天没有课，我们出去野营如何？as 用法与since相同
As Monday is a national holiday,all government offices will be closed.由于星期一是国家的法定假日，因此所有的政府办事机构都将关门休息。for表示推断的理由，对前面分句的内容加以解释或说明
It rained last night,for the ground is wet this morning.昨晚下雨了，因为今天早上地面都是湿的。介词表示因果关系
because of,due to,owing to，因为是介词，后面只能接名词。-
其他复合连词表示原因
- in that
从句放在主句后面，而且主句通常在作比较。
E-mail is different from the traditional mail in that it sends and receives mails in a second.电子邮件和传统的邮件是不同的，因为前者收发邮件可以在顷刻之间完成。 - seeing(that),now(that),considering(that),given(that)
这些连词与since相似，都是“鉴于某个事实，考虑到”的意思。 - not that...but that
意思是：“不是因为...而是因为...” - inasmuch as,insomuch as,in as much as,in so much as
比较文绉绉，不太常用，通常只用于正式书面语或者演讲中。
- in that
-
because的否定转移
否定转移：形式上否定主句或句子的谓语，但在逻辑语义上是否定句子的其他部分。尤其是because引导的从句连胜时，往往否定because引导的从句。所以以后遇到一个否定句，如果按正常情况理解不通，就不妨考虑从否定转移角度来翻译。否定转移为我们理解句子的意思提供一个新的方向。
You don't love a woman because she is beautiful.你不是因为一个女人的美貌而爱她。
don't在形式上是否定谓语love，实际上是否定原因从句。
because引导的从句的翻译可分为三种情况：- 只能按正常情况翻译
- 两种翻译都可以，具体如何理解要看上下文
- 只能按否定转移来翻译
否定转移不局限于because引导的原因从句，还可以否定句中其他成分。若是在口语中，句中什么词重读就否定什么词。
I didn't come here to scold you.我来这里不是为了要批评你。
目的状语从句
- 常用连词有：so that,in order that,that。目的从句中常含有情态动词，比如may/might/can/could等。
I turned off the TV in order that my roommate could study in peace and quiet.我关掉了电视，好让我的室友安静地学习。
I spoke slowly and clearly so that the audience could understand me.我讲的既慢又清晰，以便听众能听懂我的话。
We climbed high (so) that we might get a better view.我们爬到高外，以便能看得更清楚。 - 要强调目的状语从句时，可将so that或in order that引导的从句置于句首。
In order that my roommate could study in peace and quiet,I turned off the TV. - 可以用不定式来将目的状语从句简化。in oder that,so that,that对应不定式三种结构：in order to do,so as to do,to do。so as to不能置于句首。
- 如果需要不定式逻辑主语要用in oder for sb. to do sth，此时往往因为句子主语和不定式逻辑主语不一致。
- 其他连词的用法：lest(以免，以防止),for fear that(生怕)和in case(万一)引导目的状语从句。从句谓语动词一般用情态动词should，且shoud常常被省去。
Take an umbrella with you lest it should rain.随身带把伞，以防下雨。
What has happened is that people cannot confess fully to their dreams,as easily and openly as once they could,lest they be thought pushing,acquisitive and vulgar.省去了should，相当于lest they should be。 - for fear that或lest有时具有否定意义，相当于说in order that...not。
She cleans the windows with great care lest she might break the glass.她如此小心翼翼地擦窗户，以免打破窗玻璃。(lest she might break the glass可改写为in order that she might not break the glass)
We had a meeting and talked the matter over face to face,for fear that there should be any misunderstanding.我们开了个会，又当面谈了这件事，以免发生任何误会。（for fear that there...可改写为in order that there should not be any misunderstanding.） - 还可以用in the hope that,on purpose that,for the prupose that,to the end that等来表示目的。
The teacher raised his voice on purpose that the students in the back could hear more clearly.老师提高了声音，以便 坐在后排的学生能听得更清楚。
结果状语从句
连词有：so...that,such...that,so that,such that,结果状语从句只能放在主句之后，不能放在句首。
- so...that用法
so后面接形容词或副词，偶尔接分词。- 接形容词
The moon is so large that several million people could live there.月球的大小足以容纳几百万人口。 - 接副词
The newly described languages were often so strikingly different from the well studied languages of Europe and Southeast Asia that some scholars even accused Boas and Sapir of fabricating their data.这些新近被描述的语言与已经得到充分研究的欧洲和东南亚地区的语言往往差别显著，以至于有些学者甚至指责博阿斯和萨皮尔编造了材料。 - 接分词
We are so accustomed to adopting a mask before others that we end by being unable to recognize ourselves.我们大家都如此习惯于在别人面前戴着面具，结果最终迷失了自己。
- 接形容词
- so that用法
so that引导目的状语从句与结果状语从句的区别：- 结果状语从句往往会有逗号将主句与从句隔开。
- 结果状语从句往往没有情态动词，而目的状语从句通常有情态动词。
As the dome grows,it develops seed fissures(cracks);in at least a few cases the continent may break entirely along some of these fissures,so that the hot spot initiates the formation of a new ocean.
- such...that用法
such后面接名词。
Diplomats and crabs are creatures who move in such a way that it is impossible to tell whether they are coming for going.外交官和螃蟹是行为方式相同的动物，因为我们无法判断他们是要向前走还是想往后退。 - such that用法
such that引导结果状语从句，such就相当于"so + 形容词",具体是什么形容词要根据上下文来判断。
1)His anger was such that he lost control of himself.
2)His anger was so explosive that he lost control of himself.他的怒气一下子就爆发出来，以至于无法控制自己。（1句such相当于so explosive that）
1)The weather is such that we can only stay in air-conditioned places.
2)The weather is so hot that we can only stay in air-conditioned places.天气真热，我们只能待在有空调的地方。（1句such相当于hot）
有时很难判断such可能含有的形容词意义。
The logic of scientific development is such that separate group of men working on the same problem in far-scattered laboratories are likely to arrive at the same answer at the same time.科学发展的逻辑就是如此，不同的研究人员，分散在不同的地方形容同样的问题，很可能同时得出完全一样的结论。 - so such的区别
- so本身是副词，主要接形容词、副词，偶尔接分词。
- so + adj./adv.
The house is so expensive that I can't afford to buy it. - so + adj. + a(n) + 单数可数名词
This is so expensive a house that I can't afford to buy it. - so many/much/few/little + 名词
so many flowers, so much patience,so few cars,so little care等
- so + adj./adv.
- such是一个限定词，其后面接名词。
- such后面接各种名词
包括可数名词，复数名可数名词，不可数名词。 - such + 形容词 + 名词
such an expensive house,such nice boys,such great patience等
与so比较：so expensive a house - 限定词 + such + 名词
一般不说such many,such much,such few,而说many such dogs,much such attention,few such cars. 因为such修饰名词，表示数量形容词修饰such。其他可用such前面限定词有:no,other,some,any,one(two,three...)等
- such后面接各种名词
- so本身是副词，主要接形容词、副词，偶尔接分词。
- 结果状语从句的简化
so...that,such..that,such that对应不定式三种结构：so...as to,such...as to,such as to.
He was such a fool as to believe him.他是如此愚蠢，竟然相信他。
He was so foolish as to believe him.他是如此愚蠢，竟然相信他。
Her voice was such as to make everyone stare.她的嗓音是如此难听/大，如果大家都盯着她看。（这里such相当于 so + 形容词，相当于Her voice was so had as to make everyone stare或Her voice was so loud as to make everyone stare.根据上下文的意思选用相当的形容词来改写） - 结果状语从句的倒装
such/so...that引导结果状语从句，为了强调，可将主句中的so或such引导的部分置于句首，构成倒装结构。
So fast does light travel that it is difficult for us to imagine its speed.光的传播速度是如此之快，以至于我们无法想象它的速度。
So terrible was the storm that the roofs were all ripped off.暴风雪如此猛烈，以至于把整个屋顶都掀翻了。
Such a fool was he that he believed her.他真是愚蠢，连她都相信。 - 其他短语连词的结果状语从句
to the degree(that),to the extent(that),to such a degree (that),to such an extent(that).放在句首表示强调，主句同样需要倒装。
To such an extent did he go on with his empty speech that some of began to doze.=
He want on with his empty speech to such an extent that some of us began to doze.
The bereaved mother was grieved to the degree that she couldn't eat anything for 3 days.这位痛失亲人的母亲是如此的悲痛，以至于连着三天没吃东西。
条件状语从句
常用连词if（如果）,unless（如果不/除非）。
If winter comes,can spring be far behind?only if（只有）与if only（只要）
must/have to do...if...be to do结构（如果...必须...,那么就不得不）
其他连词：suppose(that),supposing (that),providing/provided (that),so long as,as long as,on conditon that等。
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其他条件意味句型：
- 祈使句/省略句 + and = if 从句 + 主句
Spare the rod and spoil the child.
= If you spare the rod, you'll spoil the child 孩子不打不成器。
Give us 20 minutes and we will give you 10 years back!Let us help you realize your dreams!
= If you give us 20 minutes, we will give you 10 years back! 给我20分钟，还你10岁年轻，让我们帮助你实现梦想。 - 祈使句/省略句 + or/or else = unless 从句 + 主句
Give it back to me or (else) I'll tell your parents
=Unless you give it back to me,I'll tell your parents.把它还给我，不然我就告诉你父亲。
- 祈使句/省略句 + and = if 从句 + 主句
让步状语从句
常用连词有：though,although,even though,even if.主句前不可用but,但可用yet/still.
Although he tried hard,(yet/still) he failed.尽管他努力了，但仍然失败了。
Although I didn't know anybody at the party,I had a very good time.尽管聚会上的人我一个都不认识，但我仍然玩得很愉快。
The family is the essential presence-the thing that never leaves you,even if you find you have to leave it.对于每个人来说，家是不可或缺的，它永远为你守候，即使有一天发现你要离开它。-
表示让步转折关系的介词和副词
介词主要有：despite,in spite of,for all,notwithstanding,这些是介词只能接名词（短语），不能接从句。
In spite of his inexperience,he did a very good job.
In spite of his being inexperienced,he did a very good job.（动名词短语）尽管他没有经验，但是他表现得很不错。-
介词后面还可以接what引导的名词从句。
Despite what he achieved in medicine,he remained modest.尽管他在医学领域取得了很多成就，但是他依然很谦虚。总结：表示让步逻辑关系的介词后面可以接：名词、名词短语、动名词、what从句；表示让步关系连词后面可以接完整陈述句、形容词（相当于省略名）、分词（相当于省略句）。
置于句首的while一般表示“尽管”，引导让步状语从句
no matter wh-
可以用no matter + what,who,when,where,which,how或者whatever,whoever,whenever,wherever,whichever,however引导让步状语从句，表示“无论”。除了however外，一般都单独使用，however后面接形容词或副词，不单独使用。
We have decided to do so,whatever happens.我已经决定这么做了，无论发生什么。
Whoever may trouble you,I will help you to the last.无底谁找你麻烦，我都会帮你到底。
But however amazed our descendants may be at how far from Utopia we were,they will look just like us.但是不管我们的后代对我们离乌托邦之遥远感是多么吃惊，他们的长相将和我们一样。（amazed和however一同提到句首。）
But no matter what has happened or what will happen,you will never lose your value in God's eyes.no matter wh-和however引导的让步状语从句，从句的谓语往往会有情态动词may或might加强让步语气，有时甚至把may或might省去，只剩下一个动词原型。
Try as he will, no man breaks wholly loose from his first love,no matter who she be... We've only one virginity to lose and where we lost it there our hearts will be !不管怎么样，没有一个男人能够完完全全忘却自己的初恋，不管她是谁。因为我们的童贞只有一次，我们永远不会忘记自己奉献出来的第一次。（no matter who she be 相当于 no matter who she might be）-
as引导的倒闭句表示让步
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- 形容词置句首
Oldest in our workshop as he is,he works hardest.尽管他是我们车间最年长的一们，他工作起来最努力。 - 副词置句首
Much as i respect him,I can not agree with him.虽然我非常尊重他，但我仍旧不同意他的意见。 - 分词置句首
Praised as he was,he remained modest.尽管他受到了表扬，但仍然很谦虚。 - 名词置句首
Child as he is,he is knowledgeable.他虽然还是个孩子，但知识渊博。
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动词原型置句首
- 结构为：v. + as + 主语 + 助动词may,might,will,would,can,could,do,does,did）
Fail as I did,I would never stop trying.尽管我失败了，但我决不会停止尝试。
Try as he will,no man breaks wholly loose from his first love,........ - 若动词是及物动词，则宾语也随着动词提前：
Lose money as I did,I got a lot of experience.尽管我费了不少钱，但是获得了很多经验。 - as可以替换为that或though,尽管较少这样用，不可以用although。
Odd though it sounds,cosmic inflation is a scientifically plausible consequence of some...(though代替as来表示让步)
- 结构为：v. + as + 主语 + 助动词may,might,will,would,can,could,do,does,did）
as/so + 形容词 + as + 主谓结构，放在句首表示让步（较少见）
As much as john hates to do it,he must stay at home and study tonight.尽管约翰不愿意，但他今晚还得待在家里学习。
As amusing and perceptive as graffiti may sometimes be, it has by no means won universal approval.尽管涂鸦有时可以怡人情趣并发人深思，但它决不会赢得普通的认同。-
由whether或however引导的让步从句可以变成一个句首用be的倒装句表示让步
All substances,be they gaseous,liquid or solid,are made up of atoms.一切物质，不论是气态、液态还是固态，都是由原子构成的。（原结构：All substances,Whether they may be gaseous,liquid or solid,are made up of atoms）
Be it ever so humble,there is no place like home.金窝银窝，不如自己的草窝。（原结构：However humble it may be,there is no place like home.）
比较状语从句
前一个as是副词，后一才as是比较状语从句的连词。
as + 形容词或副词 + as
The work is not as difficult as you think.这项工作不像你想象的那么难。as + 形容词 + a(n) + 可数句词单数 + as
前一个as修饰形容词，这个形容词又修饰一个名词，形容词要置于不定冠词之前。
Rarely has a technological development had as great an impact on so many aspects of social,economic,and cultural development as the growth of electronics.很少有哪项科技的发展能像电子技术的发展这样，对我们的社会、经济以及文化等诸多方面产生如此重要的影响。（原结构是a great impact,另外注意整个句子是一个倒闭句）
Americans tend to think from small to large. Let us take as simple an example as the addressing of envelopes.美国人的思维喜欢由小到大。我们举一个写信封地址的简单例子吧。（原结构是 a simple example.）否定句中的第一个as可用so代替。
No other modern nation devotes so small a portion of its wealth to public health as the United States does.没有一个现代国家像美国这样，只把自己的财富很少一部分投入到公共卫生事业中去。为了保持句子平衡，从句还可以用倒装结构（as...as + 助动词 + 主语）
Small as it is,the ant is as much a creature as are all other animals on the earth.尽管蚂蚁很小，但是它同地球上任何其他动物一样，也是一种动物。
The computer revolution may well change society as fundamentally as did the Industrial Revolution.计算机革命对于我们人类社会的改变之深刻，就如同当年的工业革命一样。as句型一：as much as结构
很多人把as much as翻译为“和...一样多”是不对的，英语里往往表示两个事物之间程度的比较，表示“在同等程度上”。
Small as it is,the ant is as much a creature as are all other animals on the earth.翻译为“和...一样”
The atmosphere is as much a part of the earth as are its soils and the water of its lakes,rivers and oceans.地球周围的大气层，就如同地球上的泥土及湖泊、河流、海洋中的水一样，都是地球的组成部分。（as从句为一个倒闭结构）。-
as句型二：not so much...as结构
用法特点：- 结构上有两种结构：not A so much as B或者not so much A as B
- 句型的基本含义为：“与其说A倒不如说B”或者“是B，而不是A”。实际翻译中非常灵活（不是(A)...而是(B)...）。
- A与B是两个被比较的平行结构，如：同为介词短语、动词不定式、名词短语或其他平等结构。
Science moves forward,they say,not so much through the insights of great men of genius as because of more ordinary things like improved techniques and tools.他们说，科学的发展与其说源于天才伟人的真知灼见，不如说源于改进了的技术和工具等更为普通的东西。
It wasn't so much that I disliked her as that I just wasn't interested in the whole business.并不是因为我不喜欢他，而是因为我对整个事情根本就不感兴趣。
The great use of a school education is not so much to teach you things as to teach you the art of learning.学校教育的伟大作用不在于教会你多少东西，而在于教会你学习的技巧。 -
as句型三：（just）as...,so结构
用法：- 基本意思是“正如...,所以”
- 第二句可用倒装结构
Just as dark clouds connot log hide the sun,so no lies can cover up the fact.乌云遮不住太阳，谎言掩盖不了事实。Just as food nourishes the body,so do books enrich the mind.食物滋养身体，书体丰富心灵。
连词than的基本用法
1、两个同类事物才可以比较，不是同类事物无法比较
he is taller than i (am)
the weather of the South is wetther than the North. 错误
the weather fo South和the North是两个截然不同的事物，无法比较，只能用南方的天气和北方的天气这两个同类事物才能比较
2、主句中必须有比较级形式出现
there are few electronic applications more likely to raise fears regarding future employment opportunities than rebots.很少有任何一项电子技术的应用能够像机器人这样,引起了人们对未来就业机会的恐慌。
３、为保持句子平衡，从句可以全部或部分倒装
结构如下：than+助动词＋主语
On the whole,ambitious students are more likely to succeed in their studies than are those with little ambition
Foreign-born Asians and Hispanics "have higher rates of intermarriage than do U.S-born whites and blacks".在海外出生的亚洲人和西班牙人的通婚率“比出生在美国的白人和黑人的通婚率要高”。
Ichthyosaurs had a higher chance of being preserved than did terrestrial creatures because,as marine animals,they tended to live in environments less subject to erosion.与地球上的其他生物相比，鱼龙的尸骨更容易保存，因为作为水生物，它们的生活环境不易使生物的遗体腐烂。-
no more...than结构
用法特点：- 结构上：no more...than = not...any more than
- 功能上：表示两个事物之间的类比关系，than后面从句中的事物来作比，以阐明than前面的主句所表达的观点。
- 意思上：基本意思是“同...一样不”，翻译时有两种选择：
先译主句后译than引导从句，即“...不能...，就如同（than引导的从句）...不能...一样”；
先译than引导从句后译主句，即“正如（than从句）...不能...，所以...同样不能...”； - than后面的句子为肯定形式，但要译成否定意思。
There is no reason they should limit how much vitamin you take,any more than they can limit how much water you drink.正如他们没有理由限制你每天喝多少水一样，他们也绝对没有理由限制你的维生素的摄入量。
The heart is no more intelligent than the stomach,for they are both controlled by the brain.心脏和胃同样都不具有智慧，因为它们都受大脑的控制。
A fool can no more see his own folly than he can see his ears.傻瓜看不到自己的愚蠢，就像他看不到自己的耳朵一样。
Unmerited praise is no more honor than deserved blame is.不该得到的表扬和应该受批评一样不光彩。 表示倍数比较的三种句型结构
表示倍数关系的连词：time和twice
1.“倍数+比较级”结构：A is three times bigger(或其他形容词的比较级) than B
2.“倍数+as...as”结构：A is three times as big(或其他形容词原级) as B
3.“倍数+名词“结构：A is three times the size(或其他形容词对应的名词形式) of Bthe more...,the more句型结构
表示“越...,越...”,将分句中的某个成分变为比较级之后提到句首，这个比较级部分必须是各自的分 句中充当一定的成分。
- 句中错误，比较级部分没有在句中充当成分。
- 句正确比较级部分在句中做状语。
- 句中比较级部分在分句中充当表语，相当于your words are more exact;it is easier for people to understand you。
- 句中比较级部分在分句中充当宾语，也是正确的。
前半部分为从句，后半部分是主句，这就是为什么前半句常用一般现在时态，后半句用一般将来时态，类似其他状语从句“主句用将来时，从句用一般现在时”的规则，别外，翻译成汉语时，一般先译从句，后译主句。
-
A is to B what/as C is to D结构
表示事物之间的类比关系，字面意思为：“A与B之间的关系，就类似于C和D之间的关系”。
The people is to the people's army what water is to fish.军民鱼水情（人民与人民军队之间的关系，就像鱼和水的关系一样）
Case study is to harvard what the Leaning Tower is to Pisa.案例数学之于哈弗大学，就如同比萨斜塔之于比萨一样著名。
Personality is to man what perfume is to flower.人的品格，犹如花的芳香。这一句型有一个变体结构："what/as C is to D,so is A to B或A is to B"
As wather is to fish,so is the peole to the people's army.军民鱼水情
As blood vessel is to a man's body,so is railway is to transportation.人体的血管对于整个人体来说，就如同铁路网络对于交通一样重要。
方式状语从句
-
连词：as,like,as if,as though,the way等
When in Rome,do as the Romans do 入乡随俗
Do it the way you were taught 按照教给你的那样做
He looks as though/as if he is an actor 他看上去像一个演员like用法，这段话很经典：
Work like you don't need the money.
Love like you've never been hurt.
Dance like nobody's watching.
Sing like nobody's listening.
Live like it's heaven on earth.
去工作吧，犹如你不需要金钱。
去爱吧，犹如你从未曾被伤害过。
去舞蹈吧，犹如无人在一旁观看。
去歌唱吧，犹如无人在一边谛听。
热爱生活吧，犹如这里是人间乐土。 as引导方式状语从句
as引导状语从句修饰句子的谓语部分。
Church as we use the word refers to all religious institutions, be they Christion,Islamic,Buddhist,Jewish,and so on.我们所使用的“教派”一词指所有宗教团体，不管他们是基督教、伊斯兰教、佛教还是犹太教等。（be they为让步状语倒装结构）as引导方式状语从句可倒装
结构一般为："as + 助动词 + 主语",as往往是代替被省略的谓语部分。
Some Asian nations and regions reiterated their opposition to a war,as did many of their citizens who worry Bush has already given up on hopes for a peaceful resolution to the crisis.一些亚洲国家和地区重申了他们反对战争的立场，他们的许多公民也持同样的立场，因为他们担心小布什已经放弃了和平解决这一危机的希望。（as后从句为倒装，谓语被省略，应该是as many of their citizens...reiterated their opposition to a war.）
Short-term memory is weakened,as are abilities to make decision and to concentrate.瞬间记忆的能力会下降，决策力和集中力同样也会减弱。（as从句为倒装，完整句子相当于：as abilities to make decision and to concentrate are weakened.）-
as的特殊用法：用于否定结构
一般as翻译成“正如”，否定结构不这样翻译。否定句有两种结构：- as前面句子是否定的，as所在的句子本身是肯定的。（as译为“不像”）
He is not arguing,as many do,that we can no longer think straight because we do not talk proper.他并没有像许多人那样，认为因为我们话说得不好，就不会正确地思维了。
Far from advocating a withdrawal from American culture,as did some of his contemporaries,he recommended a cultural pluralism through which artists could enrich the culture of America.
他并没有像同时代的人那样提倡与美国文化完全分离，而是主张一种文化多元主义，艺术家们借此可以丰富美国文化。(随然没有否定词not，但far from表示否定,as后面结构为倒装结构) - as前面句子是肯定的，as所在的句子本身是否定的。（as译为“但，然而”）
A sob rolled up in me. I flung up my hands and cried as I never had in my life.此时我非常想哭,于是我就用双手捂住脸,大声哭起来,而我以前从未这么哭过。
He could love the child as he did not love Charles.他可以爱上这个孩子，然而他却不爱查尔斯。
- as前面句子是否定的，as所在的句子本身是肯定的。（as译为“不像”）
