英语三大从句.doc

复合句【语法要点】复合句是由一个主句加一个或几个从句所构成的句子。从句只用作句子的一个成分，不能独立。根据从句在句子中的作用，可分为名词性从句、定语从句和状语从句三类。（一）名词性从句名词性从句包括主语从句、表语从句、宾语从句、同位语从句。其关联词有连接词that、if、whether；疑问代词who、what、which和疑问副词when、where、how、why等。1.名词性从句句法结构：从属连词thatwhether主语从句That he will come is certain.（that不可省）Whether she is coming or not doesnt matter too much.（不能用if）宾语从句I think（that）he will be all right in a few days.I went in and asked if（=whether）they had a cheap suit.I wonder whether（不能用if）it is true or not.表语从句The fact is（that）I have never been there.The question is whether（不能用if）it is worth doing.同位语从句The fact that she had not said anything surprised all of us.They asked me the question whether the work was worth doing.连接代词thatwhowhomwhosewhich主语从句Who will help him is not known.What he said is very important.Which side will win is not clear.宾语从句（1）作及物动词的宾语。例如：I really dont know what he is doing.Do you know who/whom they are waiting for?He asked whose dictionary it was.He cant tell which method they will use for the experiment.（2）作介词的宾语。例如：Pay attention to what the teacher said.I wondered to whom he had given the letter.表语从句That is what he is worried about.The question is who will come here.The question is which team will win the match.连接副词wherewhenwhyhow主语从句Where she has gone is not known yet.When they will start is not known yet.Why he did it wasnt quite clear.How he became a great scientist is known to us all. 宾语从句I dont know where we are going to have the meeting.Please tell me when we shall discuss our work plan.Do you know why he said that?Will you tell me how I can get to the railway station?表语从句That is where he was born.This is why he is late.This is how he did it.The question is when he will be back.同位语从句I have no idea when he will come back.You have no idea how worried I was.The problem is where we can get so much money. 2.名词性从句的其它用法：1）if不能引导表语从句。连接代词who、what、whose、which不能引导同位语从句。2）有时as、as if/though、because也可以引导表语从句，能跟表语从句的谓语动词一般为系动词be、seem、look等。例如：Things are not always as they seem to be. 事情并不总是像表面上看来的那样。It looks as if it were going to rain. It is because you eat too much. 3）介词宾语不可以用which来引导，而要用what来引导。例如：We can learn what we did not know. He will talk to us about what he saw in the U.S.4）连词that引导的名词性从句除能用在except、but、in后之外很少作介词的宾语，。其它一些介词的宾语从句如果由连词that引导，则需用it先行一步作形式宾语。例如：He is a good student except that he is careless.You may depend on it that they will support you.5）若主句谓语动词是及物动词make、find、think、see、hear等，则把宾语从句置于宾语补足语之后，用it作形式宾语。例如：We find it necessary that we practise spoken-English every day.6）某些作表语的形容词或过去分词后常接宾语从句，如sure、happy、glad、certain、pleased、afraid、surprised、satisfied等，连词that可省略，有的语法书称之为状语从句。例如：I am sure that he will succeed.I am afraid you dont understand what I said.Mother was very pleased her daughter had passed the exams.7）连接代词whoever、whatever、whichever也可引导宾语从句。例如：I will show you whatever you want to see.You may choose whoever you like. I will take whichever fits the sockets.（插座）8）同位语从句一般跟在某些表示抽象概念的名词后面，用以说明名词所表示的具体内容。常跟同位语从句的名词主要有：idea、news、fact、promise、answer、belief、condition、doubt、fear、hope、order、problem、proof、question、reply、report、suggestion、thought、 truth等。由连词that引导同位语从句既无语法功能，也无词汇意义，只是引导词；由连词whether引导同位语从句无语法功能，但有词汇意义“是否”；由连词when、where、how引导同位语从句在句中分别作作时间、地点和方式状语。注意关联词只能用whether不能用if表示“是否”的情况如下：A)在表语从句和同位语从句中。例如：The question is whether the film is worth seeing.The news whether our team has won the match is unknown.B)在主语从句中，只有it作形式主语时whether和if均可。否则，也只能用whether。例如：Whether we shall attend the meeting hasnt been decided yet.It hasnt been decided whether/if we shall attend the meeting.C)在介词之后（介词往往可以省略）。例如：It all depends (on) whether they will support us.D)后面直接跟动词不定式时。例如：He doesnt know whether to stay or not.E)与or not连用时。例如：We didnt know whether or not she was ready. 关联词if、whether均可使用的情况如下：A)引导宾语从句，但当宾语从句是否定句时，一般用if引导。例如：I wonder if/whether the news is true or not. I dont care if it doesnt rain.B)在“be+形容词”之后。例如：He was not sure whether/if it is right or wrong.用if引导宾语从句如果会引起歧义，应避免使用if而用whether。试比较：Please let me know if you want to go. Please let me know whether you want to go.（if从句既可理解为宾语从句，也可理解为条件状语从句）doubt作“怀疑”解接宾语从句时，主句为肯定句用whether或if，主句为否定句或疑问句用that。10）it作形式主语that所引导的主语从句常由代词it作形式主语。且wh-系列引导词引导的从句均可。例如： It makes everyone happy that the girl is still alive. It doesnt matter too much whether hes coming or not.It is still open to question who is to head the group. 谁领导这个小组还没定下来。 常以it作形式主语的句型有：It +be+形容词(obvious、true、natural、surprising、good、wonderful、funny、possible、likely、certain、probable)+that从句It +be+名词词组(no wonder、an honour、a good thing、a pity、no surprise)+that从句It +be+过去分词(said、reported、thought、expected、decided、announced、arranged)+that从句It +seem、happen等不及物动词及短语+that从句It +doesnt matter(makes no difference, etc)+连接代词或连接副词引导的主语从句当that引导的主语从句出现在疑问句中时，也要以it作形式主语，而把主语从句后置。例如：Is it true that the scientist will give us a lecture next week?（二）定语从句在复合句中修饰名词或代词的从句叫定语从句。被修饰的名词或代词叫先行词。引导定语从句的关系代词有who、whom、whose、which、that等和关系副词where、when、why等。关系代词和关系副词在定语从句中担任句子成分。而引导引导非限定性定语从句的关系代词有who、whom、whose、which、of which等，这些关系代词都不能省略，通常不用关系代词that。例如：I have two sisters, who are both students.关系词whowhichthatwhosewherewhen指代人物、地点等动物、物、地点等所有者地点时间例如：This is the man who helped me. They have a dog whose barking drives me mad.I know the reason why he came late. This is the place where we lived for 5 years.I will never forger the day when I met Mr. Liu. The doctor whom you are looking for is in the room.注意先行词表示地点时，有时用where，有时用that引导定语从句。这时要根据从句的谓语动词是及物的还是不及物的，是及物的就用that(which),否则就用where。例如;This is the house where he lived last year.This is the house that (which) he visited last year.关系代词which、who或that在限定性定语从句中作宾语时可省略。例如：Amsterdam is the place we like most.They are looking for a person (who) they can rely on.在定语从句中，若先行词指人，其关系代词可用who、whom，也可用that。例如：The girl who/that is speaking at the meeting is our monitor.在下列情况下多用或须用who。关系代词在从句中作主语时。例如： The doctor who treated me was very experienced. 给我治病的医生是很有经验的。先行词为all、anyone、one、ones、those、people等时。例如：All who heard the news were excited. 所有听到这消息的人都感到兴奋。Those who want to go please sign their names here. 想去的人请在这里签名。在非限制性定语从句中。例如：Toms father, who is over sixty, still works hard. 在被分隔的定语从句中。例如：A new teacher will come tomorrow who will teach you German. 在以there be开头的句子中。例如：There is a strange who wants to see you.一个句子中带有两个定语从句，其中一个关系代词是that，另一个须用who。例如：The student who was praised at the meeting is the monitor that is very modest and studied very hard. 在会上受到表扬的学生是班长，他谦虚好学。whose引导定语从句应注意以下几点：whose引导定语从句，其先行词不仅可以指人，还可以指物。例如：It was a meeting whose importance I didnt realize at the time. whose在定语从句中可与它修饰的名词一起作介词宾语，与介词放在先行词与从句之间。例如：The boss in whose department Mr. King worked had heard about the accident.Tom, on whose bike I went to school is a friend of mine. whose的先行词指物时，可用of which代替whose，但词序不同。例如：The novel whose title is Red and Black is very interesting. (=the title of which) 2.介词+关系代词中介词的选择介词的选择要看三方面：一要看和先行词是否搭配；二要看和定语从句中谓语动词是否搭配；三要根据定语从句的意义来选择。例如：This is the car by which I went to Jinan. (by car)Tomorrow we will have a meeting at which we will discuss some problems. (at the meeting)The student to whom I spoke has gone home. (speak to) 3.which和that引导定语从句的区别which在从句中作主语或谓语动词及介词的宾语。that在定语从句中可以指人或物，在从句中作主语或谓语动词的宾语。但不能放在介词后面作介词宾语。例如： This is the book which you want.The building which stands near the river is our school.The room in which there is a machine is workshop. The letter that I received was from my father.（1）只能用which不能用that的情况引导非限制性定语从句。关系词在从句中作介词宾语且位于介词之后。例如：This is the house in which I once lived.（2）用that的情况先行词既有人又有物时先行词为不定代词修饰时（all、few、little、much、something、nothing、anything等）先行词前有形容词最高级或序数词所修饰时先行词被all、any、every、few、little、no、some等修饰或被the only、the very、the same、the last、just等修饰时关系代词在从句中作表语时there be结构 例如： All that we have to do is to practise every day.The first lesson that I learned will never be forgotten.I have read all the books (that) you gave me.He is the only person that I want to talk to.They talked of things and persons that they remembered in the school.The village is no longer the one that used to be. 注意whom、which作介词宾语时，介词一般可放在which之前，也可放在原来的位置上，在有介词的动词固定词组中，介词只能放在原来的位置上。例如：This is the person whom you are looking for.当主句是以who或which开头的特殊疑问句时，定语从句须用that，以免与先行词重复。例如：Who is the boy that was here just now? 4.as引导的定语从句1)as用作关系代词和关系副词引导限定性定语从句，并在从句中作定语、表语或状语，构成the sameas, suchas等结构。例如：I like the same book as you do. (as作宾语)I shall do it in the same way as you did. (as作状语)2)as引导非限定性定语从句。as在定语从句中作主语、表语或宾语，这个定语从句是说明整个句子，位置可前、可中、可后，意为“正如、好像”。例如：Such stamps as you have collected are very valuable.As we all know, he studies very hard. (as作宾语) They remarried, as we had expected. 常用的这种类似插入语的句式有as is said above, as is known to all, as it is等。注意关系代词在从句中作主语时，从句的谓语动词的人称和数必须和先行词保持一致。关系代词which和as在定语从句中的区别是：which不能放在句首，而as则可以；在句中时，as有“正如”、“就像”之意，而which则没有。同位语从句与定语从句的区别：定语从句是形容词性从句，引导词是关系词，关系词代替先行词的意思在定语从句中作成分；同位语从句是名词性从句引导词是连接词，that、whether、if在句中不作任何成分，连接代词和连接副词本身意义在同位语从句中作成分。例如：A. The news that they had won the game arrived soon. （同位语从句）（the news和that they had won the game无逻辑关系）B. The news that you told me yesterday is true.（定语从句）（the news在从句中相当于told的逻辑宾语）（三）状语从句状语从句在句中作状语，修饰主句中的动词、形容词或副词等。状语从句放在主句之前时，常用逗号隔开；放在主句之后，一般不用逗号。1.状语从句分类及其常用连词：类别常用连词时间状语从句when、while、as、before、after、since、until（till）、once、as soon as等地点状语从句where、wherever等原因状语从句because、since、as、now that等目的状语从句so、so that、in order that、in case、lest、for fear that等结果状语从句so that、sothat、suchthat等 条件状语从句if、unless、as/so long as、on condition that、in case、once、provide that等让步状语从句though、although、even if/though、as、when、while、no matter等比较状语从句asas、not soas、than、the morethe more等方式状语从句(just)as、as if/though等 2.引导状语从句的常见连词用法when, while和as（1）when引导的时间从句中的动词既可以是延续性动词，也可以是非延续性动词。（2）while引导的时间从句中的动词通常是延续性动词。（3）as引导的时间从句中的动词是延续性动词时，则侧重表示从句的动作和主句的动作同时发生，意为：一边一边。例如：I was fat when I was a child.When the film ended, people rushed out of the hall.He took a bath while I was preparing dinner.He sang songs as he was taking a bath.注意1）when可以作并列连词，用以连接并列句，意为：这时突然。常构成下列句式：was/were doingwhen 正在突然。例如：I was working in the garden when it began to rain.be about to dowhen 正要突然。例如：We were about to go out when the rain poured down.be on the point of doingwhen 正要突然。例如：I was on the point of going out when the telephone rang.2）when还可引导原因状语从句，意为：既然，考虑到，相当于since，considering that。例如：How can they learn anything when they spend all their spare time watching TV?3）while也可作并列连词，意为“然而”。例如：Mum was sewing while dad was watching TV.4）while还可引导让步状语从句，意为“尽管”。例如：While I admit his good points, I can see his shortcomings.till与until（1）till与until意思相同，只是till一般不放在句首。、（2）主句的谓语动词如果是延续性动词，主句要用肯定式，意为：直到为止。（3）主句的谓语动词如果是非延续性动词，主句要用否定式，意为：直到才。（4）在“It is not untilthat”（直到才）句型中，要用until不用till。（5）not until置于句首时，句子需要部分倒装。例如：I will stay here until/till the rain stops. He didnt go to bed until/till I came back.It was not until I came back that he went to bed. Not until I came back did he go to bed.before与since （1）before引导的从句中一般不用否定式谓语，常用句型有：It was/will be+时间段+before。It was not/wont be+时间段+before。例如：It was long before I came. It was not long before he told me about this affair.（2）since后的动词不同，起算的时间也不同。since+非延续性动词的过去式，从该动作发生时算起since+延续性动词的过去式，从该动作结束时算起例如：It is two years since he joined the army. It is two years since he was a soldier.because、now that/since、as与for区别项 目位置内涵语气能否回答why能否被强调because主句前或后直接因果关系强能能as主句前或后双方都知道的原因弱不能不能since/now that既然主句前for并列连词，句中间接的、推断的原因最弱不能不能例如：As it is raining, we shall not go to the park.Now that everybody is here, lets begin our meeting.He must be ill, for he is absent today. It is because he was ill that he didnt go with us.although、though与as1）三者都可以引导让步状语从句，although引导让步状语从句时用正常语序，though可用正常语序也可用倒装语序。as必须用倒装语序，从句中的表语、状语或动词原形置于句首；若表语是名词，前置要省略冠词。例如：He is unhappy, though/although he has a lot of money.Difficult as/though the task was, they managed to finish it in time.Child as/though he is, he knows a lot.2）though和although在引导让步状语从句时不可与but连用，但可以和yet连用。例如：Although/Though it was raining hard, yet they went on playing football.3）though还可作副词，意为“可是，然而”。置于句末。例如：He said he would come; he didnt, though.4）even though/if引导的让步从句中视具体情况可用陈述语气或虚拟语气。例如：Even though/if it is raining, well go there.（陈述语气） Even if I were busy, I would go.（虚拟语气）whetheror （不管还是）以及疑问词+ever与no matter+疑问词（不管/无论），也可引导让步状语从句。例如：Whether you believe or not, it is true.Whatever（=no matter what）you say, he wont believe you.Whoever you are（=no matter who you are）, you must obey the rules.unless与if not很多情况下，两者可换用。例如：You will be late unless you hurry/if you dont hurry.在下列结构中，unless与if not不可相互替代。（1）当if not引导非真实条件句时一般不可用unless。例如：If Henry hadnt been tended carefully, he couldnt have lived so long.（2）unless表示除外的唯一条件，因此常不用and连接两个unless从句，而if not不受此限制。例如：If you dont eat fresh vegetable and you dont have enough exercise, you wont keep it.（3）unless从句中可用否定词，if not从句中不可再用一个否定词I will go unless no one else does.（4）在if not从句中，常用any、yet、either、at all等非肯定词，而在unless从句中常用some、already、still、too等肯定词。例如：I will be angry if you havent spoken to her yet.I will be angry unless you have already spoken to her. as/as if/as thoughas/as if/as though都可引导方式状语从句，其中as if或as though引导的从句一般用虚拟语气，但如果从句中所叙述的情况很可能实现，也可用陈述语气。例如：Do as you are told to, or you will be fired. The old lady treats the boy as if he were her own son.in order that与so that二者都可引导目的状语从句，in order that引导的目的状语从句可置于句首，但so that在引导目的状语从句时不可置于句首。例如：He got up early so that/in order that he could catch the first bus.In order that he could catch the first bus, he got up early.除此之外，for fear that、in case与lest也可引导目的状语从句，从句谓语动词要用（should）+动词原形。sothat与suchthat 二者都可引导结果状语从句，注意其结构形式的区别：so+形容词/副词+that从句so+形容词+a/an+可数名词单数+that从句so+many/much/few/li