各类从句讲解

各类从句详解英语从句可以分为名词性从句、定语从句和状语从句三大类：下面我们逐个进行阐明：一、名词性从句（主语从句、表语从句、宾语从句、同位语从句） 主语从句、表语从句、宾语从句和同位语从句在复合句中的充当的成分和其名称相似，分别作主句的主语、表语、宾语和同位语。上述这四种从句均被称为名词性从句。所有的名词性从句均不能用逗号分开，并且它们都用相似的关联词，关联词如下： 主从连词：that (无意义), whether (与否), if (与否)（在句子中不充当任何成分） 连接代词：who (谁), whom (谁), whose (谁的), what (什么), which (哪一种) 连接副词：when (什么时候), where (什么地方), how (如何), why (为什么)主从连词只起连接作用，连接代词和连接副词除了起连接作用外，还充当从句某一种成分。此外，可以用whatever, whichever, whoever, who(m)ever等连接代词引导名词性从句，来加强语调。下面分别对多种名词性从句进行简介（一）主语从句（subject clause）在主句中用作主语的主谓构造称之为主语从句。例如： That he will come to the discussion is certain.她来参与讨论是拟定的。 That the moon moves round the earth is well known to all of us.月球绕地球转动，这是我们人们都熟知的。 When the meeting is to be held has not yet been decide. 会议什么时候召开还没有决定。主语从句放在句首，句子常常显得比较笨重，因此一般可以把it放在句首，作形式主语，而将主语从句放在背面。例如上面的句子可以分别改写为：It is certain that he will come to the discussion.It is well known to all of us that the moon moves round the earth.It has not yet been decide when the meeting is to be held.下面再举某些例句：What they are after is profit.她们追求的是利润。That he is still alive is sheer luck.她还活着全靠运气。Who did the work is unknown.谁干了这工作无人懂得。Whether she will join us wont make too much difference.It wont make too much difference whether she will join us. 她与否参与我们的活动无关紧要。Which way is more effective is still a question.It is still a question which way is more effective. 哪种措施效率更高还是个问题。（二）表语从句（predicative clause）在主句中担当表语的主谓构造称之为表语从句。One idea is that fish is the best brain food.有一种见解觉得鱼是最佳的补脑食品。The problem is where we can hold our meeting.问题是我们可以在哪儿举办会议。My question is how information is stored in the long-term memory.我的问题是信息是如何储存在长期记忆中的。That is what he really wants.那就是她真想要的东西。It seems that everything goes smoothly.似乎一切都进行得很顺利。（三）宾语从句（object clause）在主句中作谓语动词、介词及非谓语动词的宾语的主谓构造称之为宾语从句。在引导宾语从句时，附属连词that在口语中和非正式文本中常省略。（1）动词后的宾语从句We know that a parrot cant really speak.我们懂得鹦鹉不会真的说话。He wants to tell us what he thinks.她想告诉我们她所想的事情。Knowing that it was going to rain, they decided to work inside the house.懂得要下雨了，于是她们决定在室内工作。(目前分词knowing的宾语从句)I want to know whether/if you still work in the factory.我想懂得你与否还在工厂工作。（不定式to know的宾语从句）The club will give whoever wins a prize. 获胜者俱乐部将颁奖。Up to now we cant say whether his theory can stand the test.到目前为止我们还不能说她的理论与否经得住考验。A little observation will show how the temperature changes.稍加观测就可以看出温度是如何变化的。Do you know who lives in this room?你懂得谁住在这房间里吗？（2） 介词后的宾语从句He laughed at what they said. 她对她们说的话一笑置之。There is disagreement among economists about what money is and how money is measured.什么是货币以及如何计量货币在经济学家之间存在分歧。（3）形容词的宾语从句有些形容词可以用that引导宾语从句，表达说话人对某一事物的态度并带有感情色彩。常用的此类形容词有：afraid, amazed, astonished, aware, certain, confident, delighted, glad, grateful, happy, proud, sad, sorry, sure, surprised等。 “胆怯，惊讶，震惊，意识，拟定，自信，快乐，快乐，快乐，快乐，自豪，伤心，对不起，固然，惊讶”例如：I am glad that you have come. 你来了，我真快乐。I am afraid that you are wrong on this point.恐怕你在这点上是错误的。He is quite confident that he will pass the examination.她很有信心通过这个考试。（四）同位词从句（apposition clause）同位语从句就是在句子中担当同位语的主谓构造。主句中有些词义比较抽象的名词，如：belief, doubt, evidence证据, idea, fact, hope, news, possibility, question, thought等，可以用that、连接代词和连接副词引出同位语从句。There is no doubt that a large number of people benefit from heart surgery.毫无疑问，有许多人得益于心脏外科手术。I have an idea that parents should monitor监控the kind of television their children watch.我有一种想法，父母应当检查孩子看电视的内容。There is the news that some British customers will visit our company. 有消息说几种英国客户要来我公司参观。Is there any proof that the food of the plant differs from that of animals?与否有任何证据可以阐明植物性的食物不同于动物性的食物呢？We all know the fact that organization helps memorization.我们都懂得这样一种事实：把要记忆的材料组织起来有助于记忆。注意：虽然that在同位语从句中没有什么意义，但不能省略。区别：尽管由that引导的同位语从句与that引导的定语从句很相似，但两者有明显的区别。 (a) that在同位语从句中是连词，只起连接作用，无具体词义，不能在从句中充当成分；而用that引导的定语从句中，that是关系代词，在从句中充当一定成分，并有词意。 (b) 同位语从句与其先行词在逻辑上有“主系表”的关系，例如上面的第一句可以理解为：“许多人得益于心脏外科手术是毫无疑问的”上述其他各句也是如此，而定语从句则没有这种关系。（五）只可用whether但不可用if的状况if, whether引导的名词性从句表达“与否”，其异同点如下：相似点： (a) 用作宾语从句时，它们可互相替代。例如：I wonder if/whether you can help me.我想懂得你与否能协助我。 (b) 都可与or连用。例如：Please tell me if/whether they are Swedish or Danish. 诉我她们是瑞典人还是丹麦人。不同点：（只可用whether但不可用if的状况） (a) if不能用于在句首的主语从句。例如：Whether John will go remains a question. 约翰与否去还是一种问题。Whether she likes the present is not clear to me. 她与否喜欢礼物我还不清晰。但可以说Its not clear to me if/whether she likes the present. （由于没有在句首，因此可以用if） (b) if不能用于表语从句The point is whether we should lend him the money. 问题在于我们与否应当借钱给她。 (c) if不能引导介词的宾语从句I worry about whether he can pass through the crisis of his illness.我紧张她与否能度过疾病的危险期。 (d) if不能引导同位语从句They are investigating the question whether the man is trustworthy.她们调查她与否值得信赖。 (e) if后不能接or notI dont care whether you like the plan or not. 我不在乎你与否喜欢该筹划。是用if还是用whether是一种考点，但能用if的场合一定能用whether，反之则否则。 二、定语从句在复合句中修饰名词或代词的从句是定语从句（attributive clause）被定语从句修饰的词叫先行词，定语从句必须放在先行词背面。定语从句一般由关系代词：that, which, who, whom, whose和关系副词：when, where, why引出。注意区别：在名词性从句中，that是连词，在句中不充当任何成分，且没有任何意义；而在定语从句中，that是关系代词，在句中充当一定成分，并有词意。（一）由关系代词引出的定语从句关系代词which指物，在从句中作主语或宾语；who指人，在从句中作主语或宾语；whom指人，在从句中作宾语；that指人或物，常用于替代which, who, whom，在从句中作主语或宾语。whose指人或物，在从句中作定语。例如：1. There are many sounds which/that have a meaning and yet are not words.有许多声音故意义但不是词。（which/that在从句中作主语）2. The few points which/that the president stressed in his report are very important indeed.校长在报告中强调的几点的确非常重要。（which/that在从句中作宾语）3. Some people who/that are successful language learners often fail in other fields.有些在语言学习上很成功的人，在其她领域常常一无所成。（who/that在从句中作主语）4. Here is the man whom/who/that youve been looking for.这就是你始终在找的人。（whom/who/that在从句中作宾语）5. She lives in the house whose door and windows are broken.她住在门窗已经坏了的房子里。（whose指物，在从句中作定语）6. How many students are there in your class whose parents serve in the government agencies?你们班里有多少同窗的父母在政府机关工作。（whose指人，在从句中作定语）注意，在定语从句中的关系代词which, who, whom, that等，如果在从句中作宾语，也可以省略。例如上面的第二句、第四句也可以改为：The few points the president stressed in his report are very important indeed.Here is the man youve been looking for.介词提前在从句中，如果which或whom在定语从句中原为介词的宾语，那么这个介词可以提到从句之前。（但that, who不合用）例如：The girl to whom you spoke is my sister. （The girl whom you spoke to is my sister.）跟你说话的那个女孩是我妹妹。前面说过，在定语从句中，如果关系代词做宾语可以省略，但是如果是介词的宾语，则关系代词省略后，介词不能提前，例如上句可改写为：The girl you spoke to is my sister.（如果关系代词省略，to不能提前了）（二）关系副词引出的定语从句关系副词when（指时间），where（指地点），why（指因素）等引出的定语从句分别用来修饰表达时间、地点、因素的先行词。这些关系副词在从句中均作状语。例如：1. At the time when I saw him, he was well.在我看到她的时候，她身体较好。2. This is the place where the accident took place last night.这就是昨晚发生事故的地方。3. That is the reason why I am not in favor of your plan.这就是我不赞成你的筹划的因素。可以用介词which构造替代关系副词。其中：when at/in/on/during which 表达时间where in/at which 表达地点why for which 表达因素1. Do you remember the day when/on which you joined our club?还记得你加入我们俱乐部的那一天吗？2. He will always remember the day when/on which his father returned from America.她将永远记住爸爸从美国返回的那一天。3. This was the time when/at which she left for Beijing.这就是她动身去北京的时间。4. This is the house where/in which I lived two years ago.这是我两年前住过的房子。5. I dont know the reason why/for which he didnt come to the meeting yesterday morning.我不懂得她为什么没参与昨天上午的会议。（三）限制性定语从句和非限制性定语从句 定语从句根据与先行词的密切限度可分为限制性定语从句和非限制性定语从句。限制性定语从句限制性定语从句与先行词关系密切，从句是整个句子不可缺少的部分，如果去掉它，句子的意思就不完整或不明确。从句与主句之间不用逗号隔开。译成汉语时，一般先译定语从句，再译先行词。1. The distance that light travels in one second is 300thousand kilometers.光在一秒钟所走的距离为30万公里。2. Those who want to go please sign their names here.想去的人在这里签名。3. This is the place where the Anti-Japanese War broke out.这里是抗日战争爆发的地方。此外，前面所给出的例句均为限制性定语从句。非限制性定语从句非限制性定语从句与先行词的关系比较松散，从句只是对先行词的附加阐明。如果去掉它，句子的意思仍然清晰。从句与主句之间常用逗号隔开。译成汉语时，从句常单独译成一句。例如：1. Steel, which has many useful properties, is widely used in the machine-building industry.钢有许多有用的特性，因此它在机械制造业中得到了广泛的应用。2. Mr. Brown, who just came from Britain yesterday, will teach us accounting this term.布朗先生昨天刚从英国来，这学期将教我们会计学。3. She is going to spend the winter holidays in Hainan, where she has some relatives.她准备到海南度寒假，那儿她有某些亲戚。（四）as引出的定语从句as常在suchas和sameas的构造中作关系代词，引出定语从句。例如：1. Such people as you describe are rare nowadays.你描述的这种人目前已经寥寥无几了。2. Let us discuss only such question as concern everyone of us.我们只讨论与我们每个人有关的问题吧。3. I feel just the same as you do.我的感觉和你同样。4. My stand on this problem is just the same as it was four years ago.在这个问题上，我的立场和四年前同样。（五）关系代词that与which的比较在定语从句中，当先行词是物时，引导词that和which常常可以通用，但如下几种状况需注意。注意1只宜于用which，不用that的状况。(1)先行词为that，those时。Whats that which is under the desk? 在桌子底下的那个是什么？(2)引导词（关系代词）前有介词时。This is the room in which he lives. 这是她居住的房间。注意2只宜于用that，不用which的状况。(1)先行词是形容词最高档或者它的前面有形容词最高档修饰时。The film is the most interesting that I have ever seen. 这部电影是我看过的最有趣的一部。English is the most difficult subject that you will learn during these years. 英语会是这些年你学的最难的科目。(2)先行词是序数词或它的前面有last或序数词修饰时。Its the first film that I saw this year. 这是我今年看的第一部电影。Tom is always the first that comes to the classroom. Tom总是第一种到教室的人。(3)主句以疑问词who，which开头时，不用which或who，以避免反复。Which is the bike that you lost? 哪辆是你丢的自行车？(4)先行词既有人又有物时。They are taiking about the sutdents and the school that they visited yesterday. 她们正在谈论昨天访问的学生和学校。(5)先行词是all, much, little, something, everything, anything, nothing, none, the one等代词时。You should hand in all that you have. 你应当把你有的所有上交。We havent got much that we can offer you. 我们没有太多能提供应你。Is this school the one that we are going to visit tomorrow? 这所学校是我们明天要参观的那个吗？Is there anything that you want to buy? 你有什么想要买的东西吗？(6) 先行词前有no, any, few, little, all, the only, the same, the very等词修饰时。The only thing that we can do is to give you some money. 我们能做的唯一的事就是给你某些钱。There are no children that dont love their parents. 没有孩子不爱她们的父母。三、状语从句在复合句中起状语作用的从句叫状语从句（adverbial clause）。状语从句按其意义可以分为：时间、地点、因素、目的、成果、条件、比较、方式、让步等类别。下面就按状语从句的类别逐个简介。 （一）时间状语从句时间状语从句一般由下列连词引导：when, whenever, as, while, since, till, until, before, after, once, as soon as, no sooner than, hardly when, scarcely when等例如：I will discuss this with you when we meet.我们会面时再与你讨论这件事。Come and see me whenever you want to.任何时候想来就来看看我。We must strike while the iron is hot.我们必须趁热打铁。As he was making his experiments, he observed this physical phenomenon.当她在做实验时，她观测到这个物理现象。I watched her until she disappeared from sight in the distance.我看着她直到她远远地消失在视野中。You havent changed much since we met last year.自从去年我们会面以来，你变化不大。He had learned English for three years before he went to London.她去伦敦之前已学了三年英语。The sun came out soon after the storm stopped.暴风雨过后不久，太阳出来了。Ill send you the sample as soon as it is made ready.一旦样品制好，我立即给你寄去。注意：when, as, while的区别区别1: when, as, while都可以表达一段持续性时间，但表达一种时间点时，要用when, as而不能用while。例如：He entered the room when/as/while the meeting was going on.合法开会的时候她走进了房间。（开会是一种持续性时间）但是：When/as he finished the speech, the audience burst into applause.当她发言结束时，听从掌声雷动。（发言结束是一种时间点，不能用while）区别2：when除有“当的时候”之意外，尚有“当之后，然后”之意，因此从句的动作发生在主句动作之前，只能用when 引导从句，不可用as 或 while。例如：When you have finished your work, you may have a rest.当你干完活后，你可以休息一下。（从句动作在主句前，只能用when） 此外，时间状语从句还可以由某些名词引导，如：the moment, the instant, the minute, the second, the day, every time等。此外有些副词也可以引导时间状语从句，如：instantly, directly, immediately等。例如：Ill telephone you the instant I know.我一懂得就立即给你打电话。Every time I catch a cold, my nose runs.我一感冒就流鼻涕。I came immediately Id eaten.我一吃完饭就来了。 （二）地点状语从句地点状语从句重要由：where, wherever引导。Where I live there are plenty of trees.我住的地方树诸多。You have the right to live where you want.你有权居住在你想住的地方。Wherever I am I will be thinking of you.不管我在哪里我都会想到你。 Sit wherever you like.你想坐在哪里就坐在那里。Wherever you go you will see great changes that have taken place in that city.不管你走到哪里，你都会看到那座都市发生的巨大变化。 （三）因素状语从句因素状语从句常常由下列连词引导：because, as, since, for, in that, now (that), seeing (that), considering (that), not thatbut that等。其中because一般放在主句背面（有时也可放在句首）；其语调比as, since要强，在回答why引导的疑问句时，必须用because回答；since一般放在句首，常表达已为人们所知的因素或理由；语调比because要弱；as可放在句首或句末，语调相对更弱；for不能用于句首，只能用于主句后，for引导的从句并不阐明主句行为发生的直接因素，只是一种解释，语调要比because弱得多。例如：She has just missed her bus because the timetable has changed.由于汽车时刻表变了，她没有赶上汽车。As the weather was fine, we decided to climb the mountain.由于天气较好，我们决定爬山。Since he is busy, I wont trouble him.既然她很忙，我就不打扰她了。He felt no fear, for he was very brave.她没有感到恐惊，由于她很勇敢。(for不能用在句首)in that, now (that), seeing (that), considering (that)这几种连词与as, since的意义相近，均有“鉴于某种事实，因素是”的意思，例如：A gas differs from a solid in that it has no definite shape.气体不同于固体就在于它没有一定的形状。Now that all are present, lets start the discussion.既然全都出席了，我们就开始讨论。Seeing (that) she was seriously ill, they sent for the doctor.鉴于她病情严重，她们派人请了医生。not thatbut that表达：“不是(由于)，而是(由于)”。He left a bit worried, not that his students were not working hard, but that they cared little for their health.她有些着急，不是由于她的学生不努力学习，而是由于她们不太注意身体健康。注意：因素状语从句与成果状语从句常可互换：例如：John flew into a rage because I took no notice of him.由于我没有注意到约翰，她气愤了。I took no notice of John, so that he flew into a rage.我没有注意到约翰，成果她气愤了。上面可以看出，本来的因素状语从句变为了主句，而本来的主句变为了成果状语从句。 （四）目的状语从句目的状语从句一般由that, so that, in order that, lest, for fear that等引导例如：They set out early that they might arrive at the station in good time.她们很早就出发了，以便及时赶到车站。Lets take the front seats so that we can see more clearly.我们坐前排吧，这样可以看得更清晰某些。We should do our utmost in order that we may be able to over fulfill the task.为了超额完毕任务，我们应当全力以赴。He took his umbrella with him lest it rain.她带了雨伞，以防下雨。Batteries must be kept in dry places for fear that electricity leak away.电池一定要放在干燥的地方，以免漏电。注意有时目的状语从句要用虚拟语调，例句请参照有关“虚拟语调”的章节。 （五）成果状语从句成果状语从句一般由：so that, sothat, suchthat等引导。例如：He made a wrong decision, so that half of his lifetime was wasted.她作了错误的决定，成果毁掉了半生。The problem is so complicated that it will take us much time to work it out.这道题这样复杂，我们要用诸多时间才干解决。The mountain is so high that she cant climb it up to the top.那座山太高了，她无法登上山顶。He ran so fast that his brother couldnt catch up with him.她跑得太快了，她弟弟赶不上她。The aircraft was flying at such a high altitude that we could hardly see it.飞机飞行的高度是这样的高，以致于我们几乎看不到它。He is such a naughty boy that he becomes unwelcome in his neighborhood.她是那么个淘气的孩子，以至在邻里中不受欢迎。 （六）条件状语从句条件状语从句可由下列连词引导：if, unless, on condition (that), suppose/supposing (that), provided/providing (that), as/so long as, in case等。If it snows tomorrow, we will build a snowman.明天如果下雪，我们就堆雪人。If you are not too tied, lets go out for a walk.如果你不太累，我们去散散步。Youll be late unless you hurry.如果不赶紧的话，你会迟到的。（ unless ifnot ）Ill lend you my computer on condition (that) you keep it in good shape.如果你能保持我的计算机的良好状态，我就可以借给你用。Suppose we are late, what will he say?如果我们迟到，她会说什么？Supposing we cant get the necessary data, what shall we do?如果我们弄不到必要的数据，那我们怎么办呢？Providing you promise not to tell anyone else, Ill explain the secret.只要你保证不告诉任何人，我就把这个秘密讲给你听。In case it rains, do not expect me.万一下雨，就不要等我了。He will do anything as long as it is interesting.只要故意义，她什么都乐意干。有些条件状语从句可以或必须使用虚拟语调，详见“虚拟语调”。 （七）比较状语从句比较状语从句可由下列连词引导：than, asas, not so/asas, thethe等。Bill is taller than Bob (is).比尔比鲍勃高。I can walk faster than you can run.我走得比你跑得还要快。He is a greater painter than people suppose (he is).她是一种比人们想像的更伟大的画家。Tom works as hard as John (dose).汤姆和约翰工作同样努力。Her mother is not as tall as she (is).她妈妈没有她高.注意：than, asas从句与主句构造上相似的部分常省略，只留下相比较的部分。如：I know you better than he (knows you).我比她更理解你。注意区别：I know you better than him.我理解你比理解她更多。阐明：本句中的than是介词，背面要用代词的宾格him，而上一句的than是连词，引导的是比较状语从句，虽然背面的成分省略，代词也要用主格he。但是，有时虽然从句与主句构造相似，但意义不同，从句一般不能省略，例如：The house is much taller than it is wide.这房子的高度比宽度大的多。thethe句型表达“越越”The sooner, the better.越快越好。The Greater the mass of a body, the greater is its inertia.物体的质量越大，它的惯性就越大。Actually, the busier he is, the happier he feels.事实上，她越忙越快乐。 （八）方式状语从句比较状语从句可由下列连词引导：as, as if/thoughI did just as you told me.我正是按照你说的办的。Please state the facts as they are.请如实地陈述事实。It looks as if/though its going to rain.看起来仿佛要下雨了。注意：as if引导的从句，即可以是陈述语调，也可以是虚拟语调。但两者体现的意思不同。例如：He walk as if he is drunk.她走起路来仿佛喝醉了。（陈述语调，有也许真的喝醉了）He walk as if her were drunk.她走起路来仿佛喝醉了似的。（虚拟语调，在说话人看来，她并没有喝醉） （九）让步状语从句让步状语从句可由下列连词引导：although, though, as, even if/though, however, whatever, no matter how/what/where/when, whetheror等although与though意义基本相似，都表达“虽然”，只是although语调更重，常用于句首。例如：Although he is poor, he is honest.她虽然空，但是诚实。Air has weight, though it is very light.虽然空气很轻，但它有重量。注意，although, though用于引导状语从句，but用于引导并列句，although, though与but不能同步使用。Try as I might, I couldnt lift the stone.尽管我可以试一试，但我不也许举起那块石头。（要倒装）Even though you say so, I do not believe it.虽然你这样说，我也不相信。However hard he tries, he never seems able to do the work satisfactorily.尽管她做出努力，但她似乎历来不能令人满意地完毕工作。Whatever you say she never listens.不管你说什么，她都不听。No matter where you go on the earth, you will feel the gravity.无论你走到地球的什么地方，你都会感觉到地引力。He keeps on with his physical training in the winter no matter how cold it is.不管冬每天气多冷，她总是坚持体育锻炼。Well start our meeting on time whether he comes or not.无论她来不来，我们将准时开会。