从句讲解
定语从句
一。I 关系代词引导的定语从句
关系代词所代替的先行词是人或物的名词或代词，并在句中充当主语、宾语、定语等成分。关系代词在定语从句中作主语时，从句谓语动词的人称和数要和先行词保持一致。
1）who, whom, that
这些词代替的先行词是人的名词或代词，在从句中作主语和宾语。例如：
Is he the man who/that wants to see you? 他就是你想见的人吗？（who/that在从句中作主语）
He is the man whom/ that I saw yesterday. 他就是我昨天见的那个人。（whom/that在从句中作宾语）
2） whose 用来指人或物，（只用作定语, 若指物，它还可以同of which互换）。例如：
They rushed over to help the man whose car had broken down. 那人车坏了，大家都跑过去帮忙。
Please pass me the book whose （of which） cover is green. 请递给我那本绿皮的书。
3）which, that所代替的先行词是事物的名词或代词，在从句中可作主语、宾语等。例如：
A prosperity which / that had never been seen before appears in the countryside.
农村出现了前所未有的繁荣。（which / that在句中作宾语）
The package （which / that）you are carrying is about to come unwrapped. 你拿的包快散了。
（which / that在句中作宾语）
II. 关系副词引导的定语从句
关系副词可代替的先行词是时间、地点或理由的名词，在从句中作状语。
1）关系副词when, where, why的含义相当于"介词+ which"结构，因此常常和"介词+ which"结构交替使用。
There are occasions when （on which） one must yield. 任何人都有不得不屈服的时候。
Beijing is the place where（in which） I was born. 北京是我的出生地。
Is this the reason why （for which） he refused our offer? 这就是他拒绝我们帮助他的理由吗？
2）that代替关系副词，可以用于表示时间、地点、方式、理由的名词后取代when, where, why和"介词+ which"引导的定语从句，在口语中that常被省略。例如：
His father died the year （that / when / in which） he was born. 他父亲在他出生那年逝世了。
He is unlikely to find the place （that / where / in which） he lived forty years ago. 他不大可能找到他四十年前居住过的地方。
III.判断关系代词与关系副词
方法一： 用关系代词，还是关系副词完全取决于从句中的谓语动词。及物动词后面无宾语，就必须要求用关系代词；而不及物动词则要求用关系副词。例如：
This is the mountain village where I stayed last year. 这是我去年呆过的山村。
I'll never forget the days when I worked together with you.我永远不会忘记与你共事的日子。
判断改错：
（错） This is the mountain village where I visited last year.
（错） I will never forget the days when I spent in the countryside.
（对） This is the mountain village （which） I visited last year.
（对） I'll never forget the days （which） I spent in the countryside.
习惯上总把表地点或时间的名词与关系副词 where, when联系在一起。此两题错在关系词的误用上。
方法二： 准确判断先行词在定语从句中的成分（主、谓、宾、定、状），也能正确选择出关系代词/关系副词。
例1. Is this museum ___ you visited a few days age? A. where B. that C. on which D. the one
例2. Is this the museum ____ the exhibition was held. A. where B. that C. on which D. the one
答案：例1 D，例2 A
例1变为肯定句： This museum is ___ you visited a few days ago.
例2变为肯定句： This is the museum ___ the exhibition was held.
在句1中，所缺部分为宾语，而where, that, on which都不能起到宾语的作用，只有the one既做了主句的表语，又可做从句的宾语，可以省略关系代词，所以应选D。
而句2中, 主、谓、宾俱全，从句部分为句子的状语表地点，既可用副词where，又因 in the museum词组，可用介词in + which 引导地点状语。而此题中，介词on 用的不对，所以选A。
关系词的选择依据在从句中所做的成分，先行词在从句中做主、定、宾语时，选择关系代词（who, whom, that, which, whose）； 先行词在从句中做状语时，应选择关系副词 （ where 地点状语，when 时间状语，why 原因状语） 。
IV. 限制性和非限制性定语从句
1） 定语从句有限制性和非限制性两种。限制性定语从句是先行词不可缺少的部分，去掉它主句意思往往不明确；非限制性定语从句是先行词的附加说明，去掉了也不会影响主句的意思，它与主句之间通常用逗号分开。例如：
This is the house which we bought last month. 这是我们上个月买的那幢房子。（限制性）
The house, which we bought last month, is very nice.这幢房子很漂亮，是我们上个月买的。（非限制性）
2） 当先行词是专有名词或物主代词和指示代词所修饰时，其后的定语从句通常是非限制性的。例如：
Charles Smith, who was my former teacher, retired last year. 查理史密斯去年退休了，他曾经是我的老师。
My house, which I bought last year, has got a lovely garden. 我去年买的的那幢房子带着个漂亮的花园。
This novel, which I have read three times, is very touching. 这本小说很动人，我已经读了三遍。
3） 非限制性定语从句还能将整个主句作为先行词, 对其进行修饰, 这时从句谓语动词要用第三人称单数。例如：
He seems not to have grasped what I meant, which greatly upsets me.他似乎没抓住我的意思，这使我心烦。
Liquid water changes to vapor, which is called evaporation. 液态水变为蒸汽，这就叫做蒸发。
V. 介词+关系词
1）介词后面的关系词不能省略。
2）that前不能有介词。
3）某些在从句中充当时间，地点或原因状语的"介词+关系词"结构可以同关系副词when 和where 互换。
This is the house in which I lived two years ago. 这是我两年前住过的房子。
This is the house where I lived two years ago.
Do you remember the day on which you joined our club? 还记得你加入我们俱乐部的那一天吗？
Do you remember the day when you joined our club?
二。定语从句应注意问题
I。that, which区别
关系代词that的几种情况。
1． 先行词为all， everything， nothing， something， anything， little， few， much等不定代词时。先行词被all， each， few， much， every， no， some， any等不定代词修饰时。如： There is little that I can use． 几乎没有什么我能用的了。
All the books that you need are here． 你所需要的书都在这儿。
2．先行词被序数词或形容词最高级修饰时。如：
This is the first composition that he has written in English．这是他用英语写的第一篇作文。
4．先行词既有人又有物时。如：
He talked about the teachers and schools that he had visited． 他谈到了他曾拜访过的老师和学校。
5．主句是以who或which开头的疑问句时。如：
Who is the man that is speaking over there？ 在那里说话的人是谁？
6．先行词被the only，the very， the last等修饰时。如：
This is the very gun that I am looking for． 这正是我在找的枪。
7． 关系代词在从句中作表语时。如：
He is not the young man that he was thirty years ago．他已不是三十年前的那个年轻人了。
关系代词which
（1）在引导非限定性定语从句时(不能放句首)
He can speak English fluently，which impressed me most.他的英语讲得很流利，给我留下了深刻印象。
（2） 介词后
This is the house in which I have lived for 2 years.这就是我居住了两年的房子。
（3）在非限制性定语从句中，即可指一个词，也可指整个句子。
She married again, which was unexpected.
I lost my watch, which is not found yet.
II。which, as 区别
as 和which在引导非限制性定语从句时，这两个关系代词都指主句所表达的整个意思，且在定语从句中都可以作主语和宾语。但不同之处主要有两点：
(1） as 引导的定语从句可置于句首，而which不可。
As we know, smoking is harmful to one's health.
（2）the same… as；such…as 中的as 是一种固定结构, 和……一样……。
I have got into the same trouble as he (has).
III。介词+关系代词
介词+whom（人）主，谓结构
介词+which（物）主，谓结构
（介词）+whose+名词+主，谓结构=and+介词+形容词形物主代词+名词+主谓结构
（介词）+which+名词+主，谓结构=and+介词+this或that +名词+主谓结构
He is the person to whom you can turn for help.
The pencil with which he was writing broke.
He is the man from whose house (=and from his house) the picture were stolen.
We traveled together to Paris, at which place(=and at this place) we parted company.
IV.分隔式定语从句
有些定语从句和现行词之间插入一个词组，短语或别的成分，叫做分隔式定语从句
He arrived Hangzhou in 1984, where he became manager 2 years later.
名词性从句
主语从句：应注意问题
1. 主语从句的语序
主语从句要求使用陈述句语序，而非一般疑问句语序。如：
What surprised me most was that the little girl could play the violin so well.
How he was successful is still a puzzle.
2. 连接词的选用
（1）that和what的选用
that和what都可引导主语从句。what除起连接作用外，还在名词性从句中充当某些成分，可作从句的主语、宾语或表语。而that在名词性从句中不充当任何成分，无词义，只起连接词作用。
What he wants is a book. That light travels in straight lines is known to all.
（2）if和whether的选用
引导主语从句，不能用if，只能用whether。如：
Whether we will hold a party in the open air tomorrow depends on the weather.
（3）其它连接代词和副词的选用
根据主语从句的具体意义，正确的选择who, which, when, where, why, how等连接词，这些连接词既有疑问含义，又起连接作用，同时在从句中充当各种成分。如：
When we shall hold our sports meet is not decided. Who broke the glass yesterday is not clear.
（4）whatever / whoever的功用
whatever, whoever在主语从句中不含疑问意义。它引导主语从句，并在从句中作主语、宾语、表语等。whatever = anything that; whoever = anyone who。要注意和whatever, whoever引导的让步状语从句的区别
Whoever breaks the law should be punished. （主语从句）（＝Anyone who breaks the law should be punished. ）
Whoever breaks the law, he should be punished. （让步状语从句）（＝No matter who breaks the law, he should be punished. ）
3. it构成的主语从句
（1）由连词that引导的主语从句，在大多数情况下会放到句子的后面，而用代词it作形式主语。
It is well-known that the earth moves around the sun.
需要注意的是，it作形式主语代替主语从句时，要注意和as引导的定语从句的区别。试比较：
It was reported that the US was under the terrorist attack. （主语从句，有that，无逗号）
As was reported, the US was under the terrorist attack.
（定语从句，无that，有逗号）
（2）常见用it作形式主语的复合句结构
It is a fact （a good idea / a pity / a shame / no wonder / good news…）that…如：
It”s a pity that you missed the film.
It is necessary （clear / true / strange/ important / possible…）that…
需要注意的是，这类主语从句中，谓语动词很多为“（should）＋动词原形”，即要用虚拟语气。
It is necessary that you （should）master the computer.
It is important that a student learn English well.
It is said that he was killed in the earthquake. 据说他在地震中丧生了。
It seems （happened / appears / doesn”t matter / makes no difference / …）that …
It seems that they will win the game.
It makes no difference whether he will attend the meeting or not.
4。主语从句连接词that不能省略 That he didn’t like her was obvious.
The problem is when we can get a pay rise.
B 连接表语从句的连接词有：that, what, who, when, where, which, why,
He has become a teacher.=He has become what he wanted to be ten years ago.
She has remained there for an hour.=She has remained where I stood yesterday for an hour.
His suggestion is good.=His suggestion is that we should stay calm.
The question is confusing.=The question is when he can arrive at the hotel.
who will travel with me to Beijing tomorrow.
how I can persuade her to join us in the party.
whether the enemy is marching towards us.
False: The question is when can he arrive at the hotel.
Right: The question is when he can arrive at the hotel.
B 不可以用if，而用whether 连接表语从句(as if 例外）。
False: The question is if the enemy is marching towards us.
Right: The question is whether the enemy is marching towards us.
Right: It looked as if he had understood this question.
C 不像宾语从句，在有表语从句的复合句中，主句时态和从句时态可以不一致。
Right: The question is who will travel with me to Beijing tomorrow.
Right: The question is why he cried yesterday.
that引导宾语从句时，特别是在口语中 that常可省略。但在下列情况下，引导宾语从句的that一般不省略。
1）当由两个或两个以上的that引导的从句作同一个动词或介词的宾语时，第二个以及以后从句中的that不宜省略。如：
He said（that）he couldn't tell you right away and that you wouldn't understand．
2）当动词think， make，feel，consider等后用it作形式宾语来代替that引导的宾语从句时。
We think it necessary that we should practise spoken English every day．
He said that even if it rained，he would be able to come．
二者引导宾语从句时，一般可换用。但在下列情况下，通常只能用whether而不能用if。
We didn't know whether or not she was ready．比较We didn't know whether／if she was ready or not．）
Please let me know whether you like it．（若该句用if，也可理解为：如果你喜欢它，请告诉我。）
When I was a boy，my teacher told me that the earth is round．
He told me he goes to the park every day．
1）在表示建议（suggest），要求（demand，insist）和命令（order）等动词后的宾语从句中，常用“（should）＋动词原形”的形式来表示虚拟语气。如：
I suggest that we（should）have a rest now．
I wish I could fly．（用过去式表示与现在事实相反的愿望）
I wish I had known it before．（用过去完成式表示过去未实现的愿望）
I wish you would stay a little longer．（用would或would ＋动词原形来表示将来的愿望）
这是一个常见的否定转移句型。使用时常把宾语从句中的否定词not移至主句中，即主句谓语用否定式而从句谓语则用肯定式。该结构常译为“我（我们）认为……不……”。如：
这是一个复杂特殊疑问句。它由一个一般疑问句（do you think）和一个特殊疑问句（疑问词＋其它句子成分）合并而成。如：
When do you think he will be back？你认为他会什么时候回来呢？
注：常用于上面两结构的主句动词除think外，还有believe，suppose，imagine等。
The news that our team had won the match spread the whole country.
有时如果主句的谓语动词较短，为保持句子平衡，避免头重脚轻，同位语从句也常与要说明的分词分开。
Word came that he died yesterday.
1. 表示陈述意义时通常用that。注意that不能省略。例如：
The fact that he didn”t pass the college entrance examination disappointed his parents.
The king made a promise that he would make anyone rich if one could cure his illness.
2. 当名词doubt用在否定句中时，其后的同位语从句应用that引导；而用在肯定句或疑问句中时则可以用其他词来引导。
I never have the doubt that you can look after yourself.
Some people have the doubt how such a little boy can lift so heavy a box.
3. 表示“是否”的意思时只能用whether，不能用if。这一点与主语从句相似。例如：
The question whether he can finish the work within two days remains unknown.
This student asked a good question why pollution can”t be stopped.
两者作用不同，主语从句和宾语从句都是从句在主句当中充当主语和宾语；而同位语从句是一个跟在某一名词后并具体说明该名词内容的从句。例如：
（1）That the pop singer will come to this city excited everybody.
（2）Everybody is excited to hear that the pop singer will come to this city.
（3）The news that the pop singer will come to this city excited everybody.
同位语从句的名词只能是前面提到的几个有限的、有一定内涵的名词；而定语从句的先行词可以是名词、代词、主句的一部分或是整个主句。
定语从句是从句对其先行词的修饰或限制，属于形容词性从句的范畴；而同位语从句是从句对其前名词的解释，该名词与同位语从句的关系可以用“主系表”来表达。例如：
We have all heard the news that our team has won.
The news is that our team has won.
有些引导词如：how, whether可以引导同位语从句，但不能引导定语从句。what不可以引导定语从句，但却可以引导同位语从句。例如：
I have no idea what has happened to him.
<1>The order that we should throw away our luggage was received yesterday.
<2>The order （that）we received yesterday was that we should throw away our luggage.
状语从句是副词性从句，它在句子中担任状语，修饰主句的动词、形容词或副词。根据修饰的方面，状语从句可以分为以下九种。
whenever When I came into the room, he was writing a letter.
We shall go there whenever we are free.
状 when I was walking along the street when suddenly someone patted me on the shoulder from behind.
我正在街上走着，这时忽然有人从后面拍我的肩膀。 when意为“这时”或“在那个时候”,可以看作是并列句,这种用法的when分句一般位于句末。
while While it was raining, they went out.
他不在的时候我在。 while指“在某一段时间里”，“在…期间”，while引导的动作必须是持续性的。
as He hurried home, looking behind as he went.
他赶快回家，不时地一边走一边向后看。 as引导持续性动作，强调主句和从句的动作同时发生。
句 before Be a pupil before you become a teacher.
after He arrived after the game started.
till We waited till (until)he came back .
我们一直等到他回来。 如主句动词是持续性动作，常用肯定式，表示“直到…为止”
时 until She didn’t stop working until eleven o’clock .
Until he had passed out of sight, she stood there.
她站在那里看着，直到看不见他的身影。 如主句动词是瞬间动词，常用否定式，表示“直…才”“在…以前不”,从句放在句首表示强调，一般用until
Great changes have taken place in China since 1978.
I had hardly got home when it began to rain.
我刚一到家，就下雨了。=Hardly had I got home when it began to rain.
No sooner had we got to the station than the train left.
Hardly had we begun when we were told to stop.
every time, by the time, the moment
等 Every time I travelled by boat, I got seasick.
The moment I heard the song, I felt cheerful.
Next time you come ,you’ll see him.
下次你来的时候，就会见到他。 在时间状语从句中，不能用将来时或过去将来时，而要用现在时或过去时代替将来时。
wherever Where there is a will, there is a way.
Where there is water there is life.
You are free to go wherever you like.
Wherever you go, you must obey the law.
无论你去哪都要遵守法律。 where与wherever意义基本相同，但后者语气较强，多用于书面语。
状 because I came back late yesterday because I was on duty.
昨天我回来晚了，因为我值班。 because用来回答why 的问题，语气最强一般放在主句之后
句 since Since everyone is here, let’s begin our meeting.
既然大家都到了，我们开始开会。 since表示既然或全已知的理由,稍加分析即可表明的原因,多放句首
因 as As he didn’t know much English, he looked up the word in the dictionary .
由于他英语懂得不多，他在字典中查阅这个单词。 从句常放在句首，说明原因，主句说明结果，常用于口语中。
句 now that, seeing that Now (that) the weather has cleared up, we can start our journey.
Seeing (that) he was badly ill, we sent for the doctor.
鉴于他病情严重，我们派人去请医生去了。 seeing (that), now that 和since, as 意义相似，他们都有“鉴于某个事实”的意思，that可以省去。
lest = for fear that I shall write down your telephone number that I may not forget.
We’ll tell you the truth so that you can judge for yourself.
They worked harder than usual in order that they could finish the work ahead of time .
Put on more clothes lest (= for fear that ) you should catch cold.
多穿点衣服，以免患感冒。 目的状语从句中常用情态动词may (might) can (could) ,should 等放在动词之前，从句往往放在主句之后，主从句之间不用任何标点符号
so…that We turned up the radio, so that everyone heard the news.
He was so excited that he couldn’t say a word.
他十分激动，以致一句话都说不出来。 so that前有逗号为结果状语从句。
句 such…that He gave such important reasons that he was excused.他说出了这么重要的理由，得到大家的谅解。
It is such an interesting novel that all of us want to read it.
It is so interesting a novel that all of us want to read it.
这是一本十分有意思的书，大家都想看。 such…that的such后面跟名词，如果名词是单数就要用such a /an…that还可以转换用so…that，语气较强
so far as Difficulties are nothing if we are not afraid of them.
We shall go there tomorrow unless it rains.
= We shall go there tomorrow if it doesn’t rain.
So/As long as you work hard, you will succeed.
In case I forget, please remind me about it .
So far as I know, the book will be published next month.
unless从句的谓语只能用肯定式。unless和if…not同义，unless是书面语，if…not是口语，通常二者可以换用。
条件状语从句中的谓语动词的时态一般要用现在时或过去时代替一般将来时或过去将来时。
as though Draw a cat as I taught you .
He acted as if (though) nothing had happened.
They treat the black boy as if (though) he were an animal.
他们对待这黑孩子仿佛他是一头牲口。 此处as译为，按照或正如
as if或as though的意义和用法基本一样。从句中可以用现在时表示可能符合事实，也可以用虚拟语气。
although Although (Though) he was over sixty, (yet) he began to learn French.
We were not tired though (although) we had worked all day.
even though I’ll go even if (though) it rains tomorrow.
即使明天下雨，我也要去。 even if 和even though的意思为“即使”“纵使”有退一步设想的意味，多用于书面语中。
as Child as he is , he knows a lot .
Cold as it is, (= Though it is cold,)the children play outdoors.
虽然天气冷，但孩子们仍在户外玩。 as引出的状语从句多用于书面语，它比用
though或although引导的从句，语气强，更有表现力，从句常放在句首，语序部分倒装。
no matter (who, what when, where which, how…) Do it no matter what others say.
No matter how busy he was, he studied English every day.
No matter who takes up the matter for me ,I shall be very grateful.
不管谁为我处理这件事，我都将非常感激。 no matter……与 who-ever引导的让步状语从句意义基本一 样，no matter……引导的从句可是以位于主句前或主句后。
Whoever comes, he will be welcome.
such…as Mary is as old as my sister.
He doesn’t run so (as) fast as Jack (does).
Henry is not such a good worker as Peter .
享利这个工人不如彼得那样好。 连词表示同程度级的比较，肯定句用as…as否定句可用not as…as 或not so…as
句 than She has made greater progress this year than she did last year.
He bought fewer books than I (did).
他买的书比我买的少。 表示不同程度之比较，主句中用比较级的形容词或副词。
…the more The more you read, the better you understand.
The more tickets you sell, the more money you will get.
The harder you work, the greater progress you will make.
越暖和越好。 the more…the more 意思为越…越…，通常的语序为从句在前主句在后，这两个the都是表示程度的副词，用在比较级的形容词或副词前面。
句 that We are sure (that )the four modernization will be realized in China .
I’m sorry (that) I didn’t have time to write you sooner.