英语四六级语法讲解大全

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        状语从句
           状语从句就是充当句子状语的从句，它可分为时间、地点、方式、比较、原因、结果、目的、条件和让步等从句。
       
        1. 时间状语从句
        1）常用来引导时间状语从句的连接词有as, when, whenever, while, before, after, till, until, since, as soon as, hardly / scarcely … when, no sooner … than …等。如：
        He made a mistake, but then he corrected the situation before it got worse.
        Jack had scarcely / hardly seen me when he left the room.
        2) 某些表示时间的副词、名词短语和介词短语也可引导时间状语从句。如directly, immediately, the instant, the moment, the minute, the day, the year, each / every time, next time, the first / second / last time, by the time等，如：
        Directly I received your letter, I came back at once.
       
        2. 地点状语从句
           地点状语从句一般由where, wherever, everywhere和anywhere引导。如：
        Wherever he went, he was warmly welcomed.
       
        3. 原因状语从句
           原因状语从句一般由because, as, since, now that, in that, seeing that, considering that, now that … but that, by reason that, for the reason that, on the ground that等引导。如：
        As it is raining, let’s stay at home.
        A gas differs from liquid in that it has no definite shape.
       
        4. 结果状语从句
           结果状语从句由so … that, such … that, so that, such that, so, that, to such a degree that, to such an extent that, with the result that等引导。
        The shock was such that she was almost driven mad.
        The temperature rose to such an extent that the firemen had to leave the house.
           注：so和such位于句首时，主句需用倒装语序。如：
        So fierce was their dog that no one dared come near.
       
        5. 目的状语从句
           目的状语从句常由that, so that, in order that, lest, for fear that, in case等引导。从句谓语常由“can / could, may / might + 动词原形”构成，有时也用“shall / should, will / would + 动词原形”。如：
        We left early so that we could catch the first train.
        He ran away lest he (should) be caught.
       
        6. 条件状语从句
           条件状语从句由if, unless, only if（只要）, if only（但愿）, when（如果）, suppose / supposing（假如）, as / so long as（只要）, given that（假设）, provided / providing that（假如）, granted / granting (that)（假定）, on condition that（条件是……）等引导。如：
        I’ll lend it to you as long as you handle it with care.
           注：若主句为一般将来时，条件状语从句中谓语需用一般现在时代替将来时。如：
        If you are free tomorrow, I will go to see you.
           但如果从句表示的是主语的意志、志愿或以you作主语表示请求时，则用will, would。如：I’d be very glad if you would come. 如果你肯来我会非常高兴。
       
        7. 让步状语从句
           让步状语从句由as, though, although, even if / though, whatever, whoever, whichever, however, whether … or …, no matter + wh-词, be, while, granted that, for all that等引导。如：
        While / Although he has some shortcomings, he also has some good points.
        Be it rain or shine, I must go.
           注：as和though引导的让步状语从句通常用倒装结构，as必须用倒装结构，though可用也可不用倒装。这种倒装通常是把从句中的表语、状语或谓语动词放在句首。如：
        Selfish as / though he is, he is not without merits. 尽管他自私，但不是没有优点。
       
        8. 方式状语从句
           方式状语从句由as, as if / though, the way, how, as … as, not so / as … as, just as (… so)等引导。如：
        It looks as if / as though it is going to rain.
        Do it the way (that) you were told.
            
            

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        八、独立结构（the Absolute Construction）
       
           独立结构是带有自己逻辑主语的结构，又称独立主格结构。作为句子的一个语言单位，其行文简单明了，功能多样。
       
        独立结构的形式
       
        1. 名词（或主格结构）+ 动词的非谓语动词形式
        Here are the first two volumes, the third one to come out next week.
        The plan having been made, what is important is to put it into practice.
        The duty completed, he had three months’ leave.
       
        2. 名词（或主格代词）+ 形容词
        He entered the room, his nose red with cold.
        She looked at him expectantly, her eyes full of excitement and curiosity.
       
        3. 名词（或主格代词）+ 介词短语
        I stood at his left, my finger on the button, waiting for the order.
        The teacher entered the classroom, chalk in one hand, (a) textbook in the other.
       
        4. 名词（或主格代词）+ 副词
        Class over, all the students went out of the classroom.
        He put on his socks, wrong side out.
       
        5. 名词（或主格代词）+ 名词
        His first shot failure, he fired again.
        She sat alone in the room, her only company a dying fire.
           注：以上独立结构都可以看作是带being的分词复合结构的省略形式。加入being就变成了分词的复合结构。如：
        Here are the first two volumes, the third one (being) to come out next week.
        He entered the room, his nose (being) red with cold.
        I stood at his left, my finger (being) on the button, waiting for the order.
       
        6. 介词with或without引导的独立结构
           这种独立结构的一般构成为：with / without + 名/代词 + （分词、形容词、副词、不定式、介词短语）。如：
        With the old man leading, the two started towards the mountains.
        She felt nervous, with all eyes fixed on her.
        Never sleep with the window open in winter.
        With John away, we’ve got more room.
        With five minutes to go before the last train left, we arrived at the station.
        His wife came down the stairs, with her two-year-old son in her arms.
       
        7. “There being + 名词”结构
        There being no money left, we have to change our plan.
        There being no spare parts, the equipment could not be repaired at once.
       
        独立结构的句法功能
           独立结构在句中多作状语，偶尔也作定语，表示时间、条件、原因、方式、伴随或补充说明。如：
        The bell ringing, all the pupils went into the classroom.
        Weather permitting, the football match will be played next Sunday.
        The question being rather difficult, we must take time to consider it carefully.
        The brave man fought the man-eating tiger, a stick his only weapon.
        How can I work with you making all that noise?
        The war was over, without a shot being fired.
        A little boy with two of his front teeth missing ran into the room.
        Jenny in trouble was the reason for my rushing there.
            
            

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        九、倒装（Inversion）
       
           倒装是语言中的一种强调手段，通常将正常语序中较晚出现的成分移至句首。倒装主要分为全部倒装和部分倒装。
       
        全部倒装
           全部倒装又称主谓倒装，把整个谓语置于主语之前。这类倒装主要出现在如下句型中：
       
        1. 句首为there, here, now, then, thus, out, in, up, away等副词，且主语是名词时。例如：
        Here comes the bus.
        Away went the car.
        There, in the distance, stands a big tree.
        First came the president and then his wife.
        Equally inexplicable（难以理解的）was his behavior towards his son.
           需要注意，上述句型中，如果主语为代词，主语和动词部分不倒装。如：
        Away they went.
        There he comes.
       
        2. 句首为表示地点的介词词组时
           这样的介词短语有：through …, before …, after …, in front of …, at the top of …, by …等。例如：
        By his side sat a dog.
        Below the mountain ran a little stream.
       
        部分倒装
           部分倒装常出现在以下几种情况中：
       
        1. 句首为否定副词或带有否定意义的词组时
           常见词（组）有：never, nowhere, no sooner (…than), not until, infrequently, little, rarely, seldom, hardly, neither, nor, not only, in no way, by no means, in / under no circumstances等。
        Neither do we know how the universe bgan, or how it will end … if, indeed, it ends at all.
        Never will anybody move without a force strong enough to covercome the resistance.
        Never has my brother been abroad before.
        Hardly had I sat down when I heard someone knocking at the door.
        No sooner had he returned than he bought a fine house and went to live there.
       
        2. only置于句首，修饰状语（从句）时
        Only in this way can we accomplish it on time.
        Only as the air bubbles out（排出）does the water fill the container.
       
        3. 句首为表示方式及频度的副词时
        Often does he warn us not to touch the poisonous chemical.
        Well do I remember the day when it happened.
        Often had I intended to speak of it.
       
        4. 在以so (…that) 开头的句子中
        So great was the destruction that the south took decades to recover.
        So quickly did the workmen finish their work that they were given more pay.
       
        5. as引导的让步状语从句中
        Prominent as he is in his field, he remains easy-going.
        Wealthy as he is, I don’t envy him.
       
        6. 在省略了if的虚拟条件句中
        Were I you, I wouldn’t feel sorry.
        Had the captain been more careful, his ship would not have been sunk.
        Should the weather be wet, the meeting would not be held.
            
            

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        十、省略与替代（Ellipsis and Substitution）
       
           省略与替代二者有着紧密的联系，都是为了精简词语和避免重复，常常交替使用，从而使语言简洁明了，上下文联系更加紧密。
       
        省略
       
        1. 某一句子成分的省略
        (I) Beg your pardon?
        (There) Must be somebody waiting for you.
        We’ll do the best we can (do).
        Only one of us was seriously injured, and he (was injured) just slightly.
        Which of them is the better choice? — Well, it’s hard to tell (it).
        Let’s do the dishes. I’ll wash (dishes) and you dry (dishes).
        Is this your bike? — Yes, it is (mine).
        He’s a real man. — Who is (a real man)?
        If you need any of that firewood, I can give you plenty (of that firewood).
        That letter was the last (I ever received from her).
       
        2. 多个句子成分的省略
        (I’ll say) A word about your composition.
        (It is) Interesting, isn’t it?
        (Is there) Anybody in?
        (Have you) Got a light?
        How could you (say so)?
        Why (do you) not go by bus?
        Which is the best? — The red one (is the best).
        Have you finished the work? — Yes, I have (finished it).
       
        3. 从句或整句省略
        He paused as if (he were) expecting Jenny to speak.
        When (she was) asked about it, she only smiled without giving any answer.
        It is easier to make a plan than (it is) to carry it out.
        Do you like the film? — Oh, (I like it) very much.
        Shall I make a fair copy of it? — Yes, (you can make a fair copy of it) if time permits.
        You would do the same (if you were in my position).
        I asked her when she would leave, and she said she didn’t know (when she would leave).
       
        替代
       
        1. 名词性替代
           名词性替代指用替代词代替名词或名词词组。常见的名词替代词有代词one / ones, the same, the kind, the sort等。如：
        The child doesn’t like this book. Show him a more interesting one. (one = book)
        Today’s libraries are quite different from those of the past. (those = the libraries)
        I’ll have two boiled eggs, please. — I’d like the same. (the same = two boiled eggs)
       
        2. 动词性替代
           动词性替代指用替代词代替动词或动词短语。常见的动词替代词有do, do so等。如：
        John speaks French as fluently as he does German. (does = speaks)
        He said he would tell me the news, but he didn’t do so. (do so = tell me the news)
        I like playing football. — So do I. (So do I. = I like playing football, too.)
        Mary will enter the competition. — So will Joan. (So will Joan. = Joan will enter the competition.)
       
        3. 句子替代
           句子替代是指用替代词代替整个从句。主要替代词有so和not。 如：
        — Do you think he’ll come tomorrow?
        — Yes, I think so. (so = that he’ll come tomorrow)
           No, I think not. (not = that he’ll not come tomorrow)