十二、倒装结构
倒装是指句子成分不是按主语在前、谓语在后的正常语序排列，而是将谓语或谓语的一部分移到主语之前。倒装是一种修辞手段，目的是为了强调。倒装分为部分倒装和全部倒装，考试多为部分倒装。考生应掌握什么情况下需要倒装。
1.下列否定词及含有否定意义的词组修饰状语时，若置于句首，句子的主谓要部分倒装
never, no, neither, not only, hardly, scarcely, little, seldom, rarely, not until, nowhere, at no time, on no account, in no respect, in no sense, by no means, in no way, no longer, no less, no more, no sooner than, under no circumstances, in vain, still less。如：
Not only is its direct attack on their discipline, it bypasses the essence of what sociologists focus on.
Under no circumstances should we do anything that will benefit ourselves but harm the interests of the state.
2.以only修饰状语开头的句子，句子的主谓要部分倒装
only then, only at that time, only once, only in this way, only with, only through, only by, only when, only after, only because。如：
Only when you have obtained sufficient data can you come to a sound conclusion.
3.以下列副词或短语开头的句子，句子的主谓要部分倒装
often, so, well, to such a degree, to such an extent, to such extremes, to such a point，many a time。如：
So involved with their computers do the children become that leaders at summer computer camps often have to force them to break for sports and games.
4.以下列副词开头的句子，句子的主谓要全部倒装
(1)出于修辞需要，表示方向的副词：out, down, in, up, away, on。如：
Down jumped the burglar from the tenth floor when he heard someone shouted at him.
(2)出于习惯用法：here, there, now, thus, hence, then。如：
Now is your turn. There goes the bell.
(3)有时主语较长，为了使句子平衡，避免头重脚轻，主谓要全部倒装。这种情况多出现在主系表结构中。如：
Less important than ever is developing a meaningful philosophy of life.
In between these two extremes are those people who agree with the jury system as a whole, but feel that some changes need to be implemented to improve its effectiveness.
5.让步从句的倒装
(1)as引导让步状语从句，必须采用倒装结构，但不是主谓倒装，而是将被强调的内容置于句首。如：
Much as I have traveled, I have never seen anyone to equal her, in thoroughness, whatever the job.
(2)出现在句型be 主语 其他, come what may中。如：
While it's true that we all need a career, preferably a profitable one, it is equally true that our civilization has accumulated an incredible amount of knowledge-be it scientific or artistic.
The business of each day, be it selling goods or shipping them, went quite smoothly.
Come what may, I'll be on your side.
6.比较从句的倒装
as, than引导的比较从句中，如果主语是名词短语且较长，经常采用倒装结构(不倒装也可以)。注意：这种结构主语一般为名词，如果是代词则不倒装。如：
Hydrogen burns much more cleanly than do other fuels and is easy to produce.
Today's electric cars cannot go as fast as gasoline-driven vehicles because the battery does not offer the same amount of energy as does gasoline combustion.
Reading is to the mind as is exercise to the body.
(1)如果谓语动词是单个实义动词，倒装时需根据人称和时态加助动词do。如：
Little did we expect that he would fulfill his task so rapidly.
(2)考生要广义理解"句首"的概念，注意从句的句首和并列分句的句首均为句首。如：
Suddenly, Gallup's name was on everyone's lips; not only was he the prophet of the moment, but it was generally believed that he had founded a new and most important method of prediction.<, /P>
十三、复合句--形容词性(定语)从句
定语从句的测试重点：选择正确的关系代词或关系副词。
切记：关系代词/副词一定要在从句中充当某种成分，即主语、宾语、表语或定语。指人时用who(做主语)、whom(做宾语)、whose(做定语)；指物时用which或that；指时间用when；指地点用where；指原因用why。此外还要注意如下几个问题：
1.尤其要注意whose的用法
whose在从句中做定语，修饰名词。所以，如果关系代词后面紧接的是名词，且关系代词又不在从句中做主语或宾语，那么，这个关系代词就应该是whose。如：
Of course developing a system for helping students whose needs are out of the ordinary had been a necessary step in helping those students get into the world of public education.
It is perhaps not an exaggeration to say that we shall soon be trusting our health, wealth and happiness to elements with whose very names the general public are unfamiliar.
2.介词 which的用法
如果从句中主宾成分齐全，考生便可考虑关系代词是否在从句中做状语，而状语通常用介词短语充当，于是可以得知，关系代词前面应有介词，再分析所给的选项，根据与名词的搭配做出正确选择。如：
Children are best served when schools contribute to shaping the solid foundation on which their future will be built.
However, the batteries from which they(electric vehicles) draw energy usually contain harmful chemicals, which become pollutants when the batteries are disposed of.
We are not conscious of the extent to which work provides the psychological satisfaction that can make the difference between a full and an empty life.
3.非限定性定语从句前面有逗号标志，按汉语习惯通常翻译成两个句子
切记：与汉语不同的是，英语中两个句子之间一般说来不能用逗号断开，而要用适当的连词或关系代词使它们形成从属或并列关系。据此可判断出逗号后面一句应由起连接作用的词开头。注意：有时关系代词前面还有其他附加成分。如：
Biologists believe that rainforests are the home of perhaps half the world's biotic species, about five-sixth of which have not yet been described and named.
There are two spare rooms in the building, neither of which has been provided with modern facilities.
4.as 与which用作关系代词的区别
(1)as与the same, such, so, as等关联使用。如：
As the forest goes, so goes its animal life.
(2)as和which都可以引导非限定性定语从句，但as在句中的位置比较灵活，可出现在句首、句中、句末，而which只能出现在句末，尤其是当先行词是整个句子时。如：
As is true in all institutions, juries are capable of making mistakes.
As is generally accepted, economic growth is determined by the smooth development of production.
常见的这类结构有：
as has been said before, as has been mentioned above, as can be imagined, as is known to all, as has been announced, as can be seen from these figures, as might/could be expected, as is often the case, as has been pointed out,
as often happens, as will be shown等。
5.关系代词that与which用于引导定语从句的区别
(1)如果关系代词在从句中做宾语，用that, which都可以，而且可以省略；
(2)先行词是不定代词anything, nothing, little, all, everything时，关系代词用that；
(3)先行词由形容词最高级或序数词修饰或由next，last, only, very修饰时，用that；
(4)非限定性定语从句只能用which引导；
(5)关系代词前面如果有介词，只能用which。
6.but做关系代词，用于否定句，相当于who…not, that…not
这个结构的特点是主句中常有否定词或含有否定意义的词。如：
There are few teachers but know how to use a computer.
There is no complicated problem but can be solved by a computer.
十四、复合句--名词性从句
一个句子起名词的作用，在句中做主语、宾语／介词宾语、表语、同位语，那么这个句子就是名词性从句。
1.what/whatever的用法
考生应把握：what是关系代词，它起着引导从句并在从句中担当一个成分这两个作用。如：
They lost their way in the forest, and what made matters worse was that night began to fall.
(what既引导主语从句又在从句中做主语)
Water will continue to be what it is today-next in importance to oxygen.
(what既引导表语从句又在从句中做表语)
2.whoever和whomever的区别
whoever和whomever相当于anyone who，用主格与宾格取决于其在从句中做主语还是做宾语。如：
They always give the vacant seats to whoever comes first.
(whoever在从句中做主语)
3.有关同位语从句的问题
(1)下列名词常用做同位语的先行词：
appeal, belief, conclusion, condition, conviction, doubt, evidence, fact, fear, feeling, ground(s),hope, idea, likelihood, message, news, opinion, order, plan, point, possibility, problem, promise, reply, proof, proposal, question, rumor, sign, story, suggestion, suspicion, theory, thought, truth, trouble, understanding, worry。如：
I have no doubt that he will overcome all his difficulties.
One sign that you are making progress in an art such as painting or photography is that you begin to realize how much there is to learn.
(2)引导词通常为that, 但有时因名词内容的需要，也可由whether及连接副词why, when, where, how引导。that不表示任何意义，其他词表示时间、地点、原因等。如：
The problem, where I will have my college education, at home or abroad, remains untouched.
The fact that she was a few minutes late is no reason for discharging her.
(3)同位语从句有时与先行词隔开，注意识别。如：
Evidence came up that specific speech sounds a
He recognized by babies as young as 6 months old.
(4)同位语从句与定语从句的区别：
●从意义上看，同位语从句说明名词的具体内容，定语从句则对名词进行限定、修饰；
●从结构上看，同位语从句的引导词不在从句中充当任何语法成分，定语从句的引导词在从句中必须充当一定的句子成分；
● 从先行词的词义特点看，同位语从句的先行词表达的是抽象内容，这类词数量有限，而定语从句的先行词则没有任何限制。
4.whether与if在引导名词性从句时的区别
(1)主语从句只能用whether引导；
(2)whether一般多用于宾语从句的肯定式，而if引导的从句可以有否定式；
(3)whether or not可以连在一起用，而if or not则不能，or not只能放在句末；
(4)whether可以引导介词宾语从句，if则不能；
(5)宾语从句提至谓语前面时，只能用whether引导；
(6)在question, ask后面一般只用whether，question的同位语从句也用whether引导；
(7)后接不定式时，只能用whether。
5.动词believe, expect, fancy, imagine, suppose, think后的宾语从句如为否定式，一般将否定词转移到主句谓语上，这一点在翻译时要注意与汉语表达的区别
十五、复合句--副词性(状语)从句
副词在句中起状语作用，故如果起状语作用的部分为一个句子，那么该句便是副词性从句，也称状语从句。状语从句可细分为：时间、地点、条件、原因、让步、目的、结果、比较、方式等。
状语从句的测试重点为：考查考生对主从句之间逻辑意义关系的把握，看其是否能选择正确的从属连词。
对于常见的状语从句和从属连词的常规用法，本书不想赘述，只谈谈常见从属连
词的特殊用法并提醒考生应注意的地方。
1.条件状语从句的常考知识点
(1)if与unless的用法。
if和unless都是引导条件状语从句的连词，考生应尤其注意unless的用法，因为它表示反面条件，相当于if not"如果不"、"除非"。如：
Even if automakers modify commercially produced cars to run on alternative fuels, the cars won't catch on in a big way unless drivers can fill them up at the gas station.
In debating, one must correct the opponent's facts, deny the relevance of his proof, or deny that what he presents as proof, if relevant, is sufficient.
(2)复合连词as long as，so long as，as far as，on condition that，in the event that；动词及分词provided(that)，providing(that)，given that, suppose/supposing(that)，assuming，say等引导条件状语从句。如：
If left alone by humans, they (the forests) can regenerate, as long as there are seed trees in the neighborhood and the soil has not lost all its nutrients.
You can arrive in Beijing earlier for the meeting provided you don't mind taking the night train.
Assuming he is diligent in his studies at ordinary times, he is sure to pass the test.
In the event that she has not been informed, I will tell her.(如果……)
You can go swimming on condition that you don't go too far from the river bank. (如果……)
Suppose it rained, we would still go. (假如……)
Say it was true, what would you do about it? (假如……)
(3)祈使句表示条件。如：
Talk to anyone in the drug industry, and you'll soon discover that the science of genetics is the biggest thing to hit drug research since penicillin was discovered.
Dress warmly, or else you'll catch cold.
Hurry up, or the tickets will have been sold out by the time we get there.
2.让步状语从句的常考知识点
(1)as 引导让步从句，要求用倒装结构，把强调的部分置于句首。如：
Much as he likes her, he does get irritated with her sometimes.
Tired as he was, we decided to disturb him.
Humble as it may be, there is no place like home.
(2)while引导让步从句。如:
Everybody cheats a little, some psychologists say, while others insist that most people are basically honest and some wouldn't cheat under any circumstances.
While it's true that we all need a career, preferably a profitable one, it is equally true that our civilization has accumulated an incredible amount of knowledge-be it scientific or artistic.
(3)复合连接词for all that和分词granting/granted(that)引导让步从句。如:
Granted you have made much progress, you should not be conceited.
For all that computers can provide us with great help, they shouldn't be seen as substitutes for fundamental thinking and reasoning skills.
3.时间状语从句的常考知识点
(1)before表示汉语的 "只有/必须……才能"。如:
Electronics must be programmed before they can work.必须为计算机编好程序它才能工作。
New ideas sometimes have to wait for years before they are fully accepted.有时候新的思想必须等待多年以后才能被人们完全接受。
(2)when引导时间从句时，如果出现在后半句，则表示"这/那时突然"。如：
He was almost hurt when the bus came to a sudden stop. (1991年6月四级考题)
I have just started back for the house to change my clothes when I heard the voices.
(3)when it comes to 是习惯用法，意为"当谈到……时"。如：
Doing your homework is a sure way to improve your test scores, and this is especially true when it comes to classroom tests.
(4)名词短语、介词短语each /every time, the moment/second/minute, in the time, by the time起连词作用。如:
I hope her health will have improved greatly by the time we come back next year.
If individuals are awakened each time they begin a dream phase of sleep, they are likely to become irritable even though their total amount of sleep has been sufficient.
My pain must have been apparent the moment I walked into the room, for the first man I met asked sympathetically: "Are you feeling all right?"
Mercury's velocity is so much greater than the Earth's that it completes more than four revolutions around the Sun in the time it takes the Earth to complete one.
(5)副词directly, immediately, instantly, now引导时间从句, 相当于as soon as。如:
The policemen went into action directly they heard the alarm.
4.原因状语从句的常考知识点
(1)in that引导原因从句时,有时翻译成"是因为"、"就在于"。如:
Advertising is distinguished from other forms of communication in that the advertiser pays for the message to be delivered.
Criticism and self-criticism is necessary in that it helps us to find and correct our mistakes.
(2)now that表示 "既然" ; seeing that, considering表示"鉴于"、"考虑到"。如:
Now that we have all the material ready, we should begin the new task at once.
He did poorly in the examinations, considering how hard he had tried for them.
Seeing she is lawfully enough to get married, I don't think how you can stop her.
其他引导原因状语从句的连接词语还有: for the (simple) reason that, by reason that, on the grounds that, in as much as, in so far as等。
5.while, whereas 引导对比从句
如:
While the teenage population in the United States has declined over the past decade, violent crimes committed by juveniles have sharply increased.
A baby might show fear of an unfamiliar adult, whereas he is likely to smile and reach out to another infant.
6.so…that…, with the result that, so much so that 引导结果状语从句
如:
Conversation becomes weaker in a society that spends so much time listening and being talked to that it has all but lost the will and the skill to speak for itself.
Over the years, a large number of overseas students have studied at that university with the result that it has acquired substantial experience in dealing with them.
He himself believed in freedom, so much so that he would rather die than live without it.
7.in order that, in case, for fear that, lest (用虚拟语气) 引导目的状语从句
如:
Give me your telephone number, in case I need your help.
Helen listened carefully in order that she might discover exactly what John wanted.
8.where作为连接副词的一种用法, 翻译为"在……地方"
如:
In Japan, a person's capabilities are not forced into an inflexible specialty. Where there is willingness and intelligence, there is a place within the company to try and to succeed.
Where the Atlantic Ocean crosses the equator, the trade wind causes a flow of water to the west.
十六、省略
1.形容词性(定语)从句关系代词的省略
(1)that, which 引导定语从句并在从句中做宾语时，可以省略。
(2)that引导定语从句并且从句是there be句型时，可以省略。如：
No one would have the time to read or listen to an account of everything there is going on in the world.
2.副词性(状语)从句的省略
(1)虚拟语气句省略条件连词if，从句采用倒装结构。如：
Had it not been for the timely investment from the general public, our company would not be so thriving as it is.
(2)由although, as if, if, no matter wh-, once, though, unless, until, when, where, whether, while等连词引导的表示时间、地点、条件、让步、方式的状语从句，可省略主语和助动词be,保留ing分词、ed分词或表语。这样省略的条件是：●从句中被省略的主语必须与主句的主语一致；●谓语动词必须含有be；●从句必须与主语和b
e动词一起省去，不可只省略主语而保留整个谓语，也不可只保留主语而省略谓语。如：
Though raised in San Francisco, Dave Mitchell had always preferred to record the plain facts of small-town life.
Although born in Chicago, the author is most famous for his stories about New York City.
One should never lose one's heart when confronted with temporary difficulties.
3.比较从句中主语的省略
在这种省略结构中，也可以把than或as当成关系代词。因为主语省略了，所以尤其要注意识别哪个词是省略了的主语，进而选择谓语的数、时态和语态。
These proposals sought to place greater restrictions on the use and copying of digital information than exist in traditional media.
There ought to be less anxiety over the perceived risk of getting cancer than exists in the public mind today.
The project requires more labor than has been put in because it is extremely difficult.
4.that用于引导宾语从句时，可以省略
倒装是指句子成分不是按主语在前、谓语在后的正常语序排列，而是将谓语或谓语的一部分移到主语之前。倒装是一种修辞手段，目的是为了强调。倒装分为部分倒装和全部倒装，考试多为部分倒装。考生应掌握什么情况下需要倒装。
1.下列否定词及含有否定意义的词组修饰状语时，若置于句首，句子的主谓要部分倒装
never, no, neither, not only, hardly, scarcely, little, seldom, rarely, not until, nowhere, at no time, on no account, in no respect, in no sense, by no means, in no way, no longer, no less, no more, no sooner than, under no circumstances, in vain, still less。如：
Not only is its direct attack on their discipline, it bypasses the essence of what sociologists focus on.
Under no circumstances should we do anything that will benefit ourselves but harm the interests of the state.
2.以only修饰状语开头的句子，句子的主谓要部分倒装
only then, only at that time, only once, only in this way, only with, only through, only by, only when, only after, only because。如：
Only when you have obtained sufficient data can you come to a sound conclusion.
3.以下列副词或短语开头的句子，句子的主谓要部分倒装
often, so, well, to such a degree, to such an extent, to such extremes, to such a point，many a time。如：
So involved with their computers do the children become that leaders at summer computer camps often have to force them to break for sports and games.
4.以下列副词开头的句子，句子的主谓要全部倒装
(1)出于修辞需要，表示方向的副词：out, down, in, up, away, on。如：
Down jumped the burglar from the tenth floor when he heard someone shouted at him.
(2)出于习惯用法：here, there, now, thus, hence, then。如：
Now is your turn. There goes the bell.
(3)有时主语较长，为了使句子平衡，避免头重脚轻，主谓要全部倒装。这种情况多出现在主系表结构中。如：
Less important than ever is developing a meaningful philosophy of life.
In between these two extremes are those people who agree with the jury system as a whole, but feel that some changes need to be implemented to improve its effectiveness.
5.让步从句的倒装
(1)as引导让步状语从句，必须采用倒装结构，但不是主谓倒装，而是将被强调的内容置于句首。如：
Much as I have traveled, I have never seen anyone to equal her, in thoroughness, whatever the job.
(2)出现在句型be 主语 其他, come what may中。如：
While it's true that we all need a career, preferably a profitable one, it is equally true that our civilization has accumulated an incredible amount of knowledge-be it scientific or artistic.
The business of each day, be it selling goods or shipping them, went quite smoothly.
Come what may, I'll be on your side.
6.比较从句的倒装
as, than引导的比较从句中，如果主语是名词短语且较长，经常采用倒装结构(不倒装也可以)。注意：这种结构主语一般为名词，如果是代词则不倒装。如：
Hydrogen burns much more cleanly than do other fuels and is easy to produce.
Today's electric cars cannot go as fast as gasoline-driven vehicles because the battery does not offer the same amount of energy as does gasoline combustion.
Reading is to the mind as is exercise to the body.
(1)如果谓语动词是单个实义动词，倒装时需根据人称和时态加助动词do。如：
Little did we expect that he would fulfill his task so rapidly.
(2)考生要广义理解"句首"的概念，注意从句的句首和并列分句的句首均为句首。如：
Suddenly, Gallup's name was on everyone's lips; not only was he the prophet of the moment, but it was generally believed that he had founded a new and most important method of prediction.<, /P>
十三、复合句--形容词性(定语)从句
定语从句的测试重点：选择正确的关系代词或关系副词。
切记：关系代词/副词一定要在从句中充当某种成分，即主语、宾语、表语或定语。指人时用who(做主语)、whom(做宾语)、whose(做定语)；指物时用which或that；指时间用when；指地点用where；指原因用why。此外还要注意如下几个问题：
1.尤其要注意whose的用法
whose在从句中做定语，修饰名词。所以，如果关系代词后面紧接的是名词，且关系代词又不在从句中做主语或宾语，那么，这个关系代词就应该是whose。如：
Of course developing a system for helping students whose needs are out of the ordinary had been a necessary step in helping those students get into the world of public education.
It is perhaps not an exaggeration to say that we shall soon be trusting our health, wealth and happiness to elements with whose very names the general public are unfamiliar.
2.介词 which的用法
如果从句中主宾成分齐全，考生便可考虑关系代词是否在从句中做状语，而状语通常用介词短语充当，于是可以得知，关系代词前面应有介词，再分析所给的选项，根据与名词的搭配做出正确选择。如：
Children are best served when schools contribute to shaping the solid foundation on which their future will be built.
However, the batteries from which they(electric vehicles) draw energy usually contain harmful chemicals, which become pollutants when the batteries are disposed of.
We are not conscious of the extent to which work provides the psychological satisfaction that can make the difference between a full and an empty life.
3.非限定性定语从句前面有逗号标志，按汉语习惯通常翻译成两个句子
切记：与汉语不同的是，英语中两个句子之间一般说来不能用逗号断开，而要用适当的连词或关系代词使它们形成从属或并列关系。据此可判断出逗号后面一句应由起连接作用的词开头。注意：有时关系代词前面还有其他附加成分。如：
Biologists believe that rainforests are the home of perhaps half the world's biotic species, about five-sixth of which have not yet been described and named.
There are two spare rooms in the building, neither of which has been provided with modern facilities.
4.as 与which用作关系代词的区别
(1)as与the same, such, so, as等关联使用。如：
As the forest goes, so goes its animal life.
(2)as和which都可以引导非限定性定语从句，但as在句中的位置比较灵活，可出现在句首、句中、句末，而which只能出现在句末，尤其是当先行词是整个句子时。如：
As is true in all institutions, juries are capable of making mistakes.
As is generally accepted, economic growth is determined by the smooth development of production.
常见的这类结构有：
as has been said before, as has been mentioned above, as can be imagined, as is known to all, as has been announced, as can be seen from these figures, as might/could be expected, as is often the case, as has been pointed out,
as often happens, as will be shown等。
5.关系代词that与which用于引导定语从句的区别
(1)如果关系代词在从句中做宾语，用that, which都可以，而且可以省略；
(2)先行词是不定代词anything, nothing, little, all, everything时，关系代词用that；
(3)先行词由形容词最高级或序数词修饰或由next，last, only, very修饰时，用that；
(4)非限定性定语从句只能用which引导；
(5)关系代词前面如果有介词，只能用which。
6.but做关系代词，用于否定句，相当于who…not, that…not
这个结构的特点是主句中常有否定词或含有否定意义的词。如：
There are few teachers but know how to use a computer.
There is no complicated problem but can be solved by a computer.
十四、复合句--名词性从句
一个句子起名词的作用，在句中做主语、宾语／介词宾语、表语、同位语，那么这个句子就是名词性从句。
1.what/whatever的用法
考生应把握：what是关系代词，它起着引导从句并在从句中担当一个成分这两个作用。如：
They lost their way in the forest, and what made matters worse was that night began to fall.
(what既引导主语从句又在从句中做主语)
Water will continue to be what it is today-next in importance to oxygen.
(what既引导表语从句又在从句中做表语)
2.whoever和whomever的区别
whoever和whomever相当于anyone who，用主格与宾格取决于其在从句中做主语还是做宾语。如：
They always give the vacant seats to whoever comes first.
(whoever在从句中做主语)
3.有关同位语从句的问题
(1)下列名词常用做同位语的先行词：
appeal, belief, conclusion, condition, conviction, doubt, evidence, fact, fear, feeling, ground(s),hope, idea, likelihood, message, news, opinion, order, plan, point, possibility, problem, promise, reply, proof, proposal, question, rumor, sign, story, suggestion, suspicion, theory, thought, truth, trouble, understanding, worry。如：
I have no doubt that he will overcome all his difficulties.
One sign that you are making progress in an art such as painting or photography is that you begin to realize how much there is to learn.
(2)引导词通常为that, 但有时因名词内容的需要，也可由whether及连接副词why, when, where, how引导。that不表示任何意义，其他词表示时间、地点、原因等。如：
The problem, where I will have my college education, at home or abroad, remains untouched.
The fact that she was a few minutes late is no reason for discharging her.
(3)同位语从句有时与先行词隔开，注意识别。如：
Evidence came up that specific speech sounds a
He recognized by babies as young as 6 months old.
(4)同位语从句与定语从句的区别：
●从意义上看，同位语从句说明名词的具体内容，定语从句则对名词进行限定、修饰；
●从结构上看，同位语从句的引导词不在从句中充当任何语法成分，定语从句的引导词在从句中必须充当一定的句子成分；
● 从先行词的词义特点看，同位语从句的先行词表达的是抽象内容，这类词数量有限，而定语从句的先行词则没有任何限制。
4.whether与if在引导名词性从句时的区别
(1)主语从句只能用whether引导；
(2)whether一般多用于宾语从句的肯定式，而if引导的从句可以有否定式；
(3)whether or not可以连在一起用，而if or not则不能，or not只能放在句末；
(4)whether可以引导介词宾语从句，if则不能；
(5)宾语从句提至谓语前面时，只能用whether引导；
(6)在question, ask后面一般只用whether，question的同位语从句也用whether引导；
(7)后接不定式时，只能用whether。
5.动词believe, expect, fancy, imagine, suppose, think后的宾语从句如为否定式，一般将否定词转移到主句谓语上，这一点在翻译时要注意与汉语表达的区别
十五、复合句--副词性(状语)从句
副词在句中起状语作用，故如果起状语作用的部分为一个句子，那么该句便是副词性从句，也称状语从句。状语从句可细分为：时间、地点、条件、原因、让步、目的、结果、比较、方式等。
状语从句的测试重点为：考查考生对主从句之间逻辑意义关系的把握，看其是否能选择正确的从属连词。
对于常见的状语从句和从属连词的常规用法，本书不想赘述，只谈谈常见从属连
词的特殊用法并提醒考生应注意的地方。
1.条件状语从句的常考知识点
(1)if与unless的用法。
if和unless都是引导条件状语从句的连词，考生应尤其注意unless的用法，因为它表示反面条件，相当于if not"如果不"、"除非"。如：
Even if automakers modify commercially produced cars to run on alternative fuels, the cars won't catch on in a big way unless drivers can fill them up at the gas station.
In debating, one must correct the opponent's facts, deny the relevance of his proof, or deny that what he presents as proof, if relevant, is sufficient.
(2)复合连词as long as，so long as，as far as，on condition that，in the event that；动词及分词provided(that)，providing(that)，given that, suppose/supposing(that)，assuming，say等引导条件状语从句。如：
If left alone by humans, they (the forests) can regenerate, as long as there are seed trees in the neighborhood and the soil has not lost all its nutrients.
You can arrive in Beijing earlier for the meeting provided you don't mind taking the night train.
Assuming he is diligent in his studies at ordinary times, he is sure to pass the test.
In the event that she has not been informed, I will tell her.(如果……)
You can go swimming on condition that you don't go too far from the river bank. (如果……)
Suppose it rained, we would still go. (假如……)
Say it was true, what would you do about it? (假如……)
(3)祈使句表示条件。如：
Talk to anyone in the drug industry, and you'll soon discover that the science of genetics is the biggest thing to hit drug research since penicillin was discovered.
Dress warmly, or else you'll catch cold.
Hurry up, or the tickets will have been sold out by the time we get there.
2.让步状语从句的常考知识点
(1)as 引导让步从句，要求用倒装结构，把强调的部分置于句首。如：
Much as he likes her, he does get irritated with her sometimes.
Tired as he was, we decided to disturb him.
Humble as it may be, there is no place like home.
(2)while引导让步从句。如:
Everybody cheats a little, some psychologists say, while others insist that most people are basically honest and some wouldn't cheat under any circumstances.
While it's true that we all need a career, preferably a profitable one, it is equally true that our civilization has accumulated an incredible amount of knowledge-be it scientific or artistic.
(3)复合连接词for all that和分词granting/granted(that)引导让步从句。如:
Granted you have made much progress, you should not be conceited.
For all that computers can provide us with great help, they shouldn't be seen as substitutes for fundamental thinking and reasoning skills.
3.时间状语从句的常考知识点
(1)before表示汉语的 "只有/必须……才能"。如:
Electronics must be programmed before they can work.必须为计算机编好程序它才能工作。
New ideas sometimes have to wait for years before they are fully accepted.有时候新的思想必须等待多年以后才能被人们完全接受。
(2)when引导时间从句时，如果出现在后半句，则表示"这/那时突然"。如：
He was almost hurt when the bus came to a sudden stop. (1991年6月四级考题)
I have just started back for the house to change my clothes when I heard the voices.
(3)when it comes to 是习惯用法，意为"当谈到……时"。如：
Doing your homework is a sure way to improve your test scores, and this is especially true when it comes to classroom tests.
(4)名词短语、介词短语each /every time, the moment/second/minute, in the time, by the time起连词作用。如:
I hope her health will have improved greatly by the time we come back next year.
If individuals are awakened each time they begin a dream phase of sleep, they are likely to become irritable even though their total amount of sleep has been sufficient.
My pain must have been apparent the moment I walked into the room, for the first man I met asked sympathetically: "Are you feeling all right?"
Mercury's velocity is so much greater than the Earth's that it completes more than four revolutions around the Sun in the time it takes the Earth to complete one.
(5)副词directly, immediately, instantly, now引导时间从句, 相当于as soon as。如:
The policemen went into action directly they heard the alarm.
4.原因状语从句的常考知识点
(1)in that引导原因从句时,有时翻译成"是因为"、"就在于"。如:
Advertising is distinguished from other forms of communication in that the advertiser pays for the message to be delivered.
Criticism and self-criticism is necessary in that it helps us to find and correct our mistakes.
(2)now that表示 "既然" ; seeing that, considering表示"鉴于"、"考虑到"。如:
Now that we have all the material ready, we should begin the new task at once.
He did poorly in the examinations, considering how hard he had tried for them.
Seeing she is lawfully enough to get married, I don't think how you can stop her.
其他引导原因状语从句的连接词语还有: for the (simple) reason that, by reason that, on the grounds that, in as much as, in so far as等。
5.while, whereas 引导对比从句
如:
While the teenage population in the United States has declined over the past decade, violent crimes committed by juveniles have sharply increased.
A baby might show fear of an unfamiliar adult, whereas he is likely to smile and reach out to another infant.
6.so…that…, with the result that, so much so that 引导结果状语从句
如:
Conversation becomes weaker in a society that spends so much time listening and being talked to that it has all but lost the will and the skill to speak for itself.
Over the years, a large number of overseas students have studied at that university with the result that it has acquired substantial experience in dealing with them.
He himself believed in freedom, so much so that he would rather die than live without it.
7.in order that, in case, for fear that, lest (用虚拟语气) 引导目的状语从句
如:
Give me your telephone number, in case I need your help.
Helen listened carefully in order that she might discover exactly what John wanted.
8.where作为连接副词的一种用法, 翻译为"在……地方"
如:
In Japan, a person's capabilities are not forced into an inflexible specialty. Where there is willingness and intelligence, there is a place within the company to try and to succeed.
Where the Atlantic Ocean crosses the equator, the trade wind causes a flow of water to the west.
十六、省略
1.形容词性(定语)从句关系代词的省略
(1)that, which 引导定语从句并在从句中做宾语时，可以省略。
(2)that引导定语从句并且从句是there be句型时，可以省略。如：
No one would have the time to read or listen to an account of everything there is going on in the world.
2.副词性(状语)从句的省略
(1)虚拟语气句省略条件连词if，从句采用倒装结构。如：
Had it not been for the timely investment from the general public, our company would not be so thriving as it is.
(2)由although, as if, if, no matter wh-, once, though, unless, until, when, where, whether, while等连词引导的表示时间、地点、条件、让步、方式的状语从句，可省略主语和助动词be,保留ing分词、ed分词或表语。这样省略的条件是：●从句中被省略的主语必须与主句的主语一致；●谓语动词必须含有be；●从句必须与主语和b
e动词一起省去，不可只省略主语而保留整个谓语，也不可只保留主语而省略谓语。如：
Though raised in San Francisco, Dave Mitchell had always preferred to record the plain facts of small-town life.
Although born in Chicago, the author is most famous for his stories about New York City.
One should never lose one's heart when confronted with temporary difficulties.
3.比较从句中主语的省略
在这种省略结构中，也可以把than或as当成关系代词。因为主语省略了，所以尤其要注意识别哪个词是省略了的主语，进而选择谓语的数、时态和语态。
These proposals sought to place greater restrictions on the use and copying of digital information than exist in traditional media.
There ought to be less anxiety over the perceived risk of getting cancer than exists in the public mind today.
The project requires more labor than has been put in because it is extremely difficult.
4.that用于引导宾语从句时，可以省略
热门推荐：
上一篇：考研英语专用语法手册3
下一篇：小作文针对四大特点复习
