第十四章 从句（subordinate clause）
由一个主句和一个或一个以上的从句构成的句子叫复合句。主句是句子的主体，从句只作为依属于主句的一个成分。各从句不能单独存在，一个从句必须由一个主从连词引出，而且全部用陈述语气。根据各个从句在主句中起的不同的语法作用，把从句分为关系从句、名词性从句、状语从句三大类。
1．关系从句
关系从句又叫定语从句。在复合句中，修饰某一名词或代词，用作定语的从句叫做定语从句（attributive clause）。被定语从句所修饰的词叫做先行词（antecedent）。定语从句必须放在先行词之后。引导定语从句的关联词有关系代词who、whom、whose、which、that和关系副词when、where、why等。关系代词和关系副词用来引导定语从句，在先行词和定语从句之间起纽带作用，使二者联系起来。关系代词和关系副词可作定语从句的一个成分。
1）关系代词的语法功能
关系代词可作主语、宾语、定语。
⑴作主语
关系代词在定语从句中作主语时，从句的谓语动词的人称和数应与先行词一致。
The books which are written by Qiong Yao have really carried me away.
（引导词which在句中作主语）琼瑶写的书确实吸引了我。
A plane is a machine that can fly.
飞机是会飞的机器。（引导词that在句中作主语）
The foreigner who visited our class yesterday is from America.
昨天到我班来访的外国人来自美国。（引导词who在句中作主语）
⑵作宾语
在定语从句里作宾语的关系代词在口语中常被省去。
The food（that）I cooked was delicious.
我做的饭美味可口。（引导词that，可省略）
The fish（which） we bought was not fresh.
我们买的鱼不新鲜。（引导词which，可省略）
The person to（whom）you just met is Tom.
刚才你碰到的人是汤姆。（引导词whom不可省略）
⑶作定语
关系代词whose在定语从句中作定语用。
Miss Brown is the teacher whose house caught fire last night.
布朗小姐就是昨晚房子着火的那位老师。
This is the girl whose father is our Math teacher.
这就是那个女孩，她父亲亲是我们的数学老师。
注意：关系代词whose在从句中与它所修饰的词一起作介词宾语时，可以跟介词放在主语和从句之间。
The boss in whose company Mr. Kang worked called at the hospital.
老板到医院拜访了康先生，康先生在他的公司里工作。
2）关系副词的语法功能
作状语
关系副词where, when和why在定语从句中分别作地点状语、时间状语和原因状语。
I'll never forget the day when I was enrolled in Nanjing University.
我将永远不会忘记我被南京大学录取的那天。
The factory where his father works is in the east of the city.
他父亲工作的那个工厂在城市的东部。
This is the reason why she was angry.
这就是她生气的理由。
3）关系代词的用法
英语中的关系代词有who，whom，whose，which，that和as。它们的用法如下：
⑴who，whom的用法
who和whom指人，who在定语从句中作主语；whom在定语从句中作宾语，在限制性定语从句中可省略。在口语中可用who代替whom。如：
People who question nothing can learn nothing.
不提问的人什么都学不会。
The person （whom） you should write to is Jim.
你应该给他写信的人是吉姆。（whom作宾语能省略）
His grandmother, whom she loved dearly, died in 1990.
她很爱你的祖母，她于1990年去世了。（whom引导非限制性定语从句，作宾语但不能省略）
⑵whose的用法
whose 指人或物，在定语从句中作定语，指物时常可用of which取代。
I have a friend whose mother is an engineer.
我有个朋友，他母亲是工程师。
We lived in a house whose window faces south.
我们住在窗口朝南的房子里。
⑶which 的用法
which指物，在定语从句中作主语和宾语，作宾语时，在限制性定语从句中可省略。
We needed a plant which didn't need as much water as rice.
我们需要一种不像水稻那样需要水的作物。（作主语，不能省略）
It is used to record the tickets （which） passengers buy.
它用来记录乘客所购买的车票。（作宾语，可以省略）
He is joking, which we all know.
我们都知道，他在开玩笑。（作宾语，在非限制性定语从句中不省略）
⑷that 的用法
that 多指物，有时也指人，在定语从句中作主语或宾语，指物时其用法和which大致相同，但也有区别。
All the people that come from the South are very clever.
所有来自南方的人工作都很聪明。（that指人，在从句中作主语，不能省略）
This is all （that） I can show you.
这是我能展示你的全部情况。（that指物，在从句中作宾语，常省略）
This is the best article that was written by Lu Xun.
这是鲁迅写得最好的一篇文章。（that指物，在从句中作主语，不能省略）
She is the only person （that） I can trust.
她是我唯一可以依赖的人。（that指人，在从句中作宾语，可以省略）
⑸关系代词that和which的区别
相同点：
这两个关系代词引导定语从句时，都可以指物；在从句中都可作主语或宾语；作宾语时都可省略。
The plane that （which ） has just arrived is from Beijing.
刚到达的个飞机是来自北京的。（作主语）
The film that（which） we saw last night is very interesting.
我们昨天晚上看的电影很有趣。（作宾语，可省略）
不同点:
用that，不用which的情况
①当先行词是不定代词或被它们修饰时。
all, everything, nothing, something, anything, little等不定代词时（something之后也可用which）。
To finish the job on time, all that I need is your help.
要按时完成工作，我所需要的是你的帮助。
Is there anything that I can do for you?
有什么要我做的事吗?
②当先行词被形容词最高级或序数词修饰时。
This was one of the most interesting books that were sold in this book store.
这是这家书店售出的最有趣的书之一。
The first thing that should be done is to clean the office.
该做的第一件事是打扫打扫办公室。
③当先行词有the very，the only，the same等修饰时。
That’s the only thing that we can do now.
目前我们只能这样了。
Those are the very words that he used.
那就是他的原话。
④当先行词是一个既指人又指物的并列词组时。
They were talking about the persons and things that they met in the company.
他们在谈论在公司里遇到的人和事。
They talked for about half an hour of things and persons that they remembered in the school.
他们聊起他们所能记得起的学校里的人和事来，聊了约半个钟头。
⑤当关系代词在定语从句中作表语时。
China is not the country that it was.
中国已经不是过去的中国了。
⑥当要避免与疑问词which重复时。
Which is the toy that was made in Shanghai?
哪个玩具是上海生产的?
⑦当先行词为the way, the time, the period等时，关系代词常用that，但通常被省略。
I don't like the way（that）you speak to her.
我不喜欢你对她说话的方式。
用which，不用that的情况
①引导非限制性定语从句。
Football, which is an interesting game, is played all over the world.
全世界都踢足球，它是一项有趣的运动。
Dorothy was always speaking highly of her role in the play, which ,of course, made the others unhappy.
桃乐茜总是吹嘘她在戏剧中的角色，这当然使别人不高兴。
②直接放在介词后作宾语时。
Language is the most important tool without which people can't communicate with each other.
语言是最重要的工具，没有它，人们便无法交流。
⑹关系代词who与that的区别
①当先行词是he、people、those等时，引导词常用who。
He who does not reach the Great Wall is not a true man.
不到长城非好汉。
Those who are against me, put up your hands.
反对我的人请举手。
I'll never forget the people who have helped me.
我将永远不会忘记那些帮助过我的人。
②当引导词作定语从句的表语时常用that。
He isn't the little boy that he used to be.
他再也不是过去的那个小男孩了。
He is the man that I asked for help yesterday.他就是我昨天求助的人。
⑺as的用法
①as引导限制性定语从句通常构成such...as或the same...as固定搭配，as在从句中可作主语、表语或宾语。
I like to wear the same clothes as you wore yesterday.
我喜欢穿你昨天穿的那件衣服。（作宾语）
Many of the sports were the same as they are now.
过去的许多运动项目同现在的一样。（作表语）。
Read this as often as is necessary.
根据需要反复阅读。（作主语）
②such…that…与such…as
“such…that…”表示“如此……以致……”的意思，用来引导一个结果状语从句；而“such…as…”表“像……这样的……”的意思，用来引导定语从句，as在从句中充当主、宾或表语等。
He is such a lovely man that we like him.
他是一个如此可爱的人以至于我们都喜欢他。
He is such an honest man as we respect.
他像我们所尊敬的这种诚实的人。
③the same…that…与the same as
“the same…that…”表同一人或物，而“the same…as…”表同种类的东西。试比较下列两个句子：
This is the same bike that I lost.
这就是我丢失那辆自行车。（指同一辆自行车）
This is the same bike as I lost.
这跟我丢失那辆自行车一模一样。（并不是原来的那辆自行车）
④as 引导非限制性定语从句
as作关系代词，还可用来引导非限制性定语从句，可以用来代替一个句子或单词，as引导的句子可放在句首、句末或句中。
The moon, as is known to everybody, travels round the earth once every month.
As is known to everybody, the moon travels round the earth once every month.
The moon travels round the earth once every month, as is known to everybody.
众所周知，月球一月绕地球一周。
⑻but 的用法
but既可指人，又可指物，常在定语从句中充当主语。but 本身含“否定”的意思，其作用相当于“that/which/who…not”。它前面的主句必须有“否定”的词（如no, not, little, few, hardly等）。but引导的肯定定语从句和否定的主句连用，通过双重否定达到强烈肯定的效果。
There is no mother but loves her own children.（=There is no mother that/who doesn’t’t love her children.）
没有不爱自己子女的母亲。
There were few people but were hurt.（= There were few people who/that were not hurt.）
几乎没有人不受伤。
⑼than的用法
than既可指人，又可指物，可作关系代词来引导定语从句，than前通常有比较级的词。
Don’t give children more money than is needed.
给孩子们的钱不要超过所需。
He has got more than he asked for.
他所得到的比他所要求的还要多。
Fewer friends than we had expected came to our evening party.
来参加晚会的朋友比我们预料的还要少。
4）关系副词的用法
英语中的关系副词有where，when，why等。
⑴when的用法
when指时间，修饰表时间的先行词，在定语从何中作时间状语。
He came last night when I was out.
他昨晚来时，我出去了。
Do you remember the day when I first came to your home?
你还记得我到你家的那天吗?
⑵where的用法
where指地点，修饰表地点的先行词，在定语从句中作地点状语。
The spot where the accident happened is near.
事故发生的地点就在附近。
I can still remember the bedroom where my sister and I used to sleep.
我还记得那间我妹妹和我住在一起的起居室。
She will go home where she can rest.
她要回家了，在家里她可以休息。
注意：先行词为表示时间、地点的名词时，关系词不一定都用when或where。如果关系词在定语从句中作主语或宾语，就要用关系代词which或that。
This is the factory that/which we visited last year.
这是我们去年参观的那家工厂。
I won't forget the time that we spent in the countryside.
我永远不会忘记我在农村度过的那段时光。
⑶why的用法
why指原因，修饰名词reason，在定语从句中作原因状语。
This is the reason why he was late.
这就是他迟到的理由。
Do you know the reason why he left early?
你知道他为什么早走吗？
5）“介词＋关系代词”用法
⑴介词+which在定语从句中分别作时间、地点和原因状语
介词+which在关系分句中分别作时间，地点和原因状语，代替相应的关系副词when，where和why。
I still remember the day on which （=when）I first came to school.
我仍然记得初来学校的那一天。
The factory in which （=where） I work is a large one.
我工作的工厂是一个大厂子。
This is the reason for which（=why）he was late.
这就是他为什么迟到的原因。
In the office I never seem to have time until after 5:30 p.m., by which time many people have gone home.
在办公室里，我好像只有五点半之后有时间，在此前很多人都已回家了。
注意：关系代词that在定语从句中作介词的宾语时，介词不能放在它的前面，只能放在从句中有关动词的后面。
The village that she lives in is 100 meters away.
她住在100米远的村庄里。
⑵不定代词或数词+of+which（指物）/whom（指人），在定语从句中作主语
不定代词或数词+of+which（指物）/whom（指人），在关系分句中作主语，说明整体中的部分。
China has a lot of islands, one of which is Taiwan.
中国有许多岛屿，其中之一是台湾。
⑶介词+which（指物）/whom（指人），在关系分句中作目的、方式或地点状语
这种结构中的介词一般受动词或介词后的名词所制约。
Could you tell me to whom you've sent this gift?
你能告诉我这个礼物是送给谁的吗?
⑷介词+which（指物）/whom（指人），用于被动结构的关系分句中，作状语，说明动作的发出者。
The wolf by which the sheep was killed was shot.
伤害羊的那只狼被打死了。
The man by whom the wolf was shot was a good hunter.
打死狼的那人是一个好猎手。
⑸名词+of which，代替whose+名词，在关系分句中作定语。
I saw some trees, the leaves of which （=whose leaves）were black with disease.
我看见一些树，它们的叶子因生病而发黑。
He mentioned a book, the title of which （=whose title ）I've forgotten.
他提到一本书，书的名我忘了。
⑹介词+which（指物）/whose（指人），修饰后边的名词。
It snowed all night and all day, during which time the electricity was cut off.
雪下了一天一夜，就在这期间停电了。
6）限制性定语从句和非限制性定语从句
定语从句分限制性定语从句和非限制性定语从句两种。
⑴限制性定语从句
限制性定语从句为先行词不可缺少的定语。如果将这种定语从句省去，主句的意思就会不完整或失去意义。这种从句和主句的关系十分密切，写时不用逗号分开。
This is the teacher who came to see you yesterday.
这就是昨天来看你的那位老师。（限制性定语从句）
It happened at the time when I left the office.
这件事发生在我离开办公室的时候。
⑵非限制性定语从句
非限制性定语从句和主句的关系不十分密切，只是对先行词作附加的说明，如果去掉，主句的意思仍然清楚。这种从句和主句之间往往用逗号分开，一般不用that来引导。
Yesterday, I met Li Ping, who seemed to be busy.
昨天我遇见了李平，他好像很忙。（非限制性定语从句）
In Britain, which has a population of 55. 8 million, 110,000 people die from smoking each year.
英国有5580万人口，每年有11万人口死于吸烟
⑶限制性定语从句与非限制性定语从句的区别
①形式上不同
非限制性定语从句在书写时往往用逗号和主句分开，而限制性定语从句不用逗号与主句分开。
Last night I saw a very good film，which was about the Long March.
昨晚我看了一场好电影，这部电影是关于长征的故事。
The man whom I met in the street was a worker .
我在街上遇到的那个人是个工人。
可否省略的不同
②限制性定语从句是先行词在意义上不可缺少的定语，如果去掉，主句的意思就不完整或失去意义，而非限制性定语从句是对先行词作的附加说明，即使去掉，主句的意思仍然完整。
John was the only person in my office who was invited.
约翰是我办公室中唯一受邀之人。
My mother sent me a birthday present, which cost her much money.
妈妈送我了一个生日礼物，这个礼物花了她一大笔钱。
③关系代词的不同
非限制性定语从句不能用that引出，并且关系代词在非限制性定语从句中作宾语时也不能省略，但在限制性定语从句中却恰恰相反。
This is the best film （that） I have ever seen.
这是我看过得最好的电影。
She sang a new song, which we liked very much.
她唱了一首新歌，我们都喜欢这首歌。
④翻译方式不同
限制性定语从句往往译在先行词之前，而非限制性定语从句往往译为一个并列的句子。
She is the English teacher whom we all like very much.
她就是我们都很喜欢的英语老师。
This note was left by Mary, who was here a moment ago.
这个条子是玛丽留的，她刚才到这儿来过。
⑷as与which在非限制性定语从句中的用法区别
as和which作为关系代词都可以用来引导非限制性定语从句，指代整个主句所表达的内容，在从句中作主语或宾语，但它们在用法上有区别。
①相同之处
当从句位于主句之后，引导词指代整个主句所表达的全部意义时，as和which可以互换。
He is an American, as/which I know from his accent.
他是一个美国人，那时我从他的口音上知道的。
②不同之处
A. as引导非限制性定语从句时，位置比较灵活，可位于主句之前，也可位于主句之中或之后，而which引导非限制性定语从句只能位于主句之后，不能谓语主句之前。
My young brother is good at computer , as we all know.
我弟弟特擅长学计算机，这我们家人都知道。
As is known to all, England is a developed country.
都知道,英国是一个发达的国家。
Air, as we know, is a gas.
我们知道，空气是一种气体。
He changed his mind, which made me very angry.
他改变了主意，这使我很生气。
B. which引导的从句在意义上相当于一个并列句，可以用and this代替，意思是“这件事”；as引导的从句主要起连接上下文的作用，表达说话人的观点、看法，并指出主句内容的根据或出处等。例如：
He sold his car, which surprised me. （=He sold his car, and this surprised me.）
他把车卖了,这使我感到奇怪。
He left early, which was wise.
他早早地离开，那是很明智的。
As is known to all, China is the country with largest population in the world.
众所周知，中国是世界上人口最多的国家。
C. 当which在从句中指代的是先行词本身而不是主句时，不可用as代替which。
The book, which I bought yesterday, is very instructive.
我昨天买的那本书很有教育意义。
D. 在从句中作主语时，which既可作系动词be的主语，也可作实义动词的主语，而as只可作系动词be的主语。
He married her, which was natural.
（可用as代替which）他和她结婚了，这是很自然的事。
He succeeded, which delighted him.
（不可用as代替which）他成功了，这使他很高兴。
2．名词性从句
名词性从句在复合句中起名词的作用，它包括主语从句、宾语从句、表语从句、同位语从句四大类，在句中分别用作主语、宾语、表语和同位语。
1）引导名词性从句的关联词
⑴从属连词that，whether、if
连词that本身没有意义，在从句中不担任任何句子成分，在宾语从句中有时可省略，但引导其他名词性从句时通常不省略。如：
I hear （that） he has passed the final examination.
我听说他已经通过了期末考试。
That he likes you is very obvious.
很显然他喜欢你
It so happens that I know the man.
碰巧我认识那个。
It Is certain that they will win.
他们一定会赢。
whether和if
连词whether和if本身有意义（表示：“是否”），也不充当句子成分，在从句中不可省略。
① whether可以连接所有的名词性从句，而if只能引导宾语从句。
I didn't know whether he would agree with me.
我并不知道他是否同意我的观点。（宾语从句，可用if代替whether）
The question is whether it s worth trying.
问题是值不值得试一试。（表语从句，不可用if代替whether）
Whether he right or wrong makes no difference.
他对或错都没有关系。（主语从句，不可用if代替whether）
He must answer the question whether he agrees to it or not.
他必须回答他是否同意此事这样一个问题。（同位语从句，不可用if代替whether）
②whether引导的宾语从句可作介的宾语，而if则不能。
It all depends on whether they will support us.
这完全取决于他们是否支持我们。（不用if）
Tom was worrying about whether he had hurt her feelings.
汤姆担心是否伤害了她的感情。（不用if）
③if既可引导状语从句，也可引导宾语从句。如果用if会引起歧义，应避免使用if，而用whether。
Please let me know if you want to join us.
请告诉我你是否想加入我们。（if引导的从句可被看成是宾语从句，if表示是否）
Please let me know if you want to join us.
如果你想加入我们的话，请告诉我一声。
（if引导的从句可被看成是条件状语从句，if表示如果）
Please let me know whether you want t join us.
请告诉我你是否想加入我们。（为避免引起歧义，可用whether表示是否）
⑵连接代词who, whom, whose, what, which
连接代词who, whom, whose, what, which等在从句中既起连接作用，均有意义，同时又担当主语、宾语、定语、表语等成分。
Who will win the game is easy to predict.
谁将赢得比赛很容易预测。
We are worrying about what we should do next.
我们正在为下一步该怎么办而烦恼。
Tell me whose bag it is.
告诉我这是谁的包。
No one knows who she was.
没人知道她是谁。
⑶连接副词where, when, how, why
连接副词where, when, how, why等也各自有自己的意义，在从句中既是连接词，又作状语。
I don't know where we are going to have the party.
我不知道我们将在哪儿聚会。
When she’ll be back depends much on the weather.
她什么时候回来在很大程度上要看天气。
She always thinks of how she can work well.
她总是在想怎样能把工作做好。
Why he did it will remain a puzzle forever.
他为什么这样做将永远是一个谜。
比较：
when引导的时间状语从句和名词性从句中的不同时态。
Please let me know when you leave.
你离开的时候，请告诉我一声。（when引导的是时间状语从句，从句中用一般现在时来表示将来。）
Please let me know when you will leave.
请告诉我你什么时候离开。（when引导的是宾语从句，从句中用一般将来时。）
⑷whoever, whomever, whatever, whichever, whosever
连接代词whoever = anyone who任何人, 无论谁；whatever =anything that凡是...，无论什么；whichever = anything that无论那一个, 任何一个；whomever = anyone whom （whoever的宾格形式）。Whoever comes to the party is welcome.
不论谁来参加这个聚会都欢迎。
You may do whatever you will.
你可做任何你想做的事。
I'll take whichever book interests me.
我愿买任何让我感兴趣的书。
Whosever book is the cheapest will be bought.
不管谁的书买最便宜的
You may offer the book to whomever you like.
你可把这本书给任何你喜欢的人
2）主语从句
主语从句位于谓语动词之前，整个句子用作主语。如:
Who will answer the question is hard to predict.
谁将回答这个问题很难预测。
That he hates you is very obvious.
很显然他讨厌你。
What she said is difficult to understand.
她的话很难懂。
注意：
⑴在主系表结构的句子中，如果主语从句长于表语时，往往it用作形式主语，真正的主语从句谓语表语之后。如：
It is very interesting that they all passed the exam.
他们都通过了考试真有意思。
It is a mystery how the earth was first formed.
地球刚开始是怎样形成的仍然是个谜。
⑵主语从句被看做一个句子成分，后跟单数谓语。
What she said and did is right.
她所说的和做的都是对的。
Whether he will attend the meeting remains a question.
他是否参加这个会议还不知道。
3）表语从句
表语从句放在连系动词之后，充当复合句中的表语。
⑴可接表语从句的连系动词
可接表语从句的连系动词有be, look, seem, sound, appear等。
China is no longer what she used to be.
今日的中国不再是过去的中国了。
The question remains whether they will be able to help us.
问题还是他们能否帮我们。
It appears that he has a taste for art.
看来他对艺术有一定的鉴赏力.
At that time, it seemed as if I couldn’t think of the right word anyhow.
当时，我似乎怎么也想不出一个恰当的字眼来。
⑵as, as if，though引导的表语从句
she looked just as she had looked nine years before.
她看起来还与九年前一样。
It sounds as if someone is singing out of the classroom.
听起来好像有人在教室外面唱歌。
⑶because, why引导的表语从句
I think it is because you are eating too much.
我想这是因为你吃得太多。
That's because he didn't trust me.
那是因为他不信任我。（That's because 强调原因）
That's why he got angry with me.
那正是他对我生气的原因。（That's why强调结果）
注意:
what引导的主语从句表示结果或名词reason作主语时，后面的表语从句表示原因时要用that引导，一般不宜用because。
The reason why I was happy was that my aunt would visit me.
我高兴的原因是我姑姑要来看我。
What cost him his life was that he was too careless.
使他丧命的原因是他太粗心了。
⑷使用虚拟语气的表语从句
在表示建议、劝告、命令含义的名词后的表语从句，谓语动词需用should+动词原形表示，should可省略。常见的词有：advice, suggestion, order, proposal, insistence, plan, idea等。
My suggestion is that we （should） start early tomorrow.
我的建议是我们明天一早就出发。
His proposal was that people （should） obey the traffic rules.
他的提议是人们应该遵守交通规则。
4）宾语从句
在复合句中用作动词宾语或介词宾语的从句叫宾语从句。
⑴作动词宾语
He told us（that）he was responsible for the serious mistake.
他对我们说他对这个严重的错误负责任。。
Do you know whose umbrella it is?
你知道这是谁的伞？
Give a reading list to whoever comes.
给所有来的人一份阅读书目。
注意：
doubt（怀疑）的肯定句接if /whether引导的宾语从句，但否定句和疑问句接that引导的宾语从句。
I doubt whether/ if we will succeed.
我怀疑我们是否会成功。
I do not doubt that he can recite the poem.
我相信他能把这首诗背下来。
Do you doubt that he will win？
你不相信会获胜吗？
⑵作介词的宾语
He was deeply displeased by what had occurred that day.
他对那天发生的事感到很不快。
I am curious as to what he will say.
我很想知道他要说什么。
Your success will largely depend upon what you do and how you do it.
你是否成功将主要取决于你做什么和怎样做。
They were praised or criticized according to how they had done their work.
他们受表扬还是受批评是根据他们工作好坏而定。
He goes to the library every day except when it is raining.
除了天下雨外，他每天都去图书馆。
注意：
that引导的宾语从句只用在少数介词后，如：except, in, but等。此时，that不能省略。
I know little about him except that he lives downstairs.
我对他知之甚少，只知道他住在楼下。
He differed from his classmates in that he devoted his spare time to reading.
他和他的同学们不同的地方在于他把业余时间用在阅读上。
⑶作形容词的宾语
I am not sure what I ought to say .
我不能确定我该说什么。
I'm afraid （that） you don't understand what I said.
恐怕你没领会我说的意思。
⑷用it作形式宾语的情况
和it作形式主语一样，我们常用it来做形式宾语，把真正的宾语从句放在句末，这种情况尤其出现在带复合宾语的句子中。
We thought it strange that Tom was late yesterday.
我们认为汤姆昨天迟到了挺奇怪的。
He has made it clear that he will not give in.
他已表明他不会屈服。
注意：
①宾语从句的语序
和其他词性从句一样，宾语从句必须使用陈述语序，不能用疑问语序。
How can I get to the station Can you tell me?
→Can you tell me how I can get to the station?
你能告诉我怎样去车站吗？
What does he like I wonder→I wonder what he likes.
我想知道他喜欢什么。
Where were you born He asked→He asked me where I was born.
他问我出生的地方。
②宾语从句中的时态
A.在一般情况下，宾语从句中时态要和主句相一致，尤其是主句为过去时态时。
He said that he had lived in Beijing since 1980.
他说自1980年以来他一直住在北京。
He made it quite clear that he preferred to learn English.
他明确地说他更喜欢学英语。
B.有时，宾语从句中时态也可以和主句不一致。
You can't imagine how they were excited when they won the first place in the game.
你无法想象他们获得比赛第一名时是多么的兴奋。
Can you make sure where you have put the bag?
你能确定你把袋子放哪儿了吗？
C.客观真理和自然规律的内容在宾语从句中时态保持不变。
He asked whether the earth moves around the sun.
他问地球是否绕着太阳转。
Columbus proved that the earth is round.
哥伦布证明了地球是圆的。
③关于that的省略
一般情况下，宾语从句中的that是可以省略的。但在下列几种情况下，that一般不可省略。
A.介词后面的that不能省。
Nancy is a good student except that he is sometimes naughty.
南希是好学生，只是有时比较淘气。
B.并列连词and连接两个或两个以上宾语从句，and前面的that可以省略， and的后面的that不能省略。
My uncle says （that） he has served here for twenty years and that he is going to retire next month.
我叔叔说他在这儿工作已二十年了，下个月即将退休。
C.that引导的宾语从句位于句首时，that不可省略。
That he ever did such a thing I simply don't believe.
我简直不相信他曾做过这样的事。
D.主句谓语动词与that从句之间有插入语，that不可省略。
He said that, if he could manage it, he would join the party.
他说，如果他安排得好的话，他会参加聚会的。
E.宾语从句中有其他从属连词时，that不能省略。
He told me that if it was necessary they would work all night.
他告诉我，如果需要的话，他们就干个通宵。
④宾语从句的否定转移
在think, consider, believe, suppose, expect, fancy等动词后的宾语从句，如有否定意思，一般要把否定词前移到主句的语上，从句的谓语用肯定的形式。
I don't think he can do it better than me.
我想他不会干得比我好。
I don't believe they have finished their work yet.
我相信他们还未完成他们的工作。
提示：
在下列情况下，宾语从句不否定转移：
A.think等词前有副词和表示强调的do
I really expect he won’t fail the examination.
我真希望他不会不通过考试。
I do think that he is not fair.
我确实认为他是不公正的。
B.think等词和其他词构成并列谓语
I think and hope that he won't cheat in the exam.
我想，也希望他考试不会作弊的。
C.think等词作为插入语
His decision is not wise, I think.
我觉得他的决定并不明智。
5）同位语从句
同位语从句用于对前面的名词作进一步解释，说明名词的具体内容。同位语从句一般由that引导，但也可以由whether 以及连接代词和连接副词引导。
⑴同位语从句一般跟在名词fact, hope, idea, news, doubt, suggestion, information, opinion, decision, discovery, truth, promise, statement, problem, rule等的面。
They were all very much worried over the fact that you were sick.
对你生病这件事，他们都很焦虑。
Where did you get the idea that he was ill？
你在哪儿听说他病了？
I have no idea whether he'll come or not.
我不知道他是否来。
We haven't yet settled the question where we are going to spend our summer vacation.
到哪儿去度暑假，这个问题我们还没有决定。
It is a question how he did it.
那是一个他如何做了此事的问题。
There is no doubt that we will win.
毫无疑问我们会赢的。
注意：
当含有同位语从句的主句谓语部分过短时，可以把谓语动词提前，使同位语从句与名词隔开，以避免头重脚轻的现象。
Word came that the President would come and inspect our school himself.
有消息说总统先生将亲自来视察我们学校。
⑵使用虚拟语气的同位语从句
在一些表示建议、命令、要求的名词后的同位语从句中，谓语动词用should+动词原形表示，should可省略。
This is our only request that this （should） be settled as soon as possible.
尽快解决这个问题，这是我们唯一的请求。
He made the suggestion that we go by plane.
他建议我们坐飞机。
3. 状语从句
在复合句中由从句表示的状语称作状语从句，它可以用来修饰谓语（包括非谓语动词）、定语或状语，或是整个句子。状语从句不能单独存在，通常由一个连词引起，也可以由一个起连词作用的词组引起，有时甚至不需要连词直接和主句连接起来。按其意义可以分为九种：
时间状语从句、地点状语从句、原因状语从句、目的状语从句、结果状语从句、条件状语从句、让步状语从句、方式状语从句、比较状语从句。
1） 时间状语从句
⑴时间状语从句通常由下列连词引导
When（当……时候）/whenever（无论何时）/while（当……时候）/
as（当……时候）/before（在……之前）/after（在……之后）/
until（直到……才）/till（直到……/ as soon as（一……就）
hardly…when（一……就）/no sooner…than（一……就）
例：
He was about to leave when the telephone rang.
他正要离开，忽然电话铃响了。
As the day went on, the weather got better .
日子一天天过去，天气越变越好。
While I am washing the floor, you can be cleaning the windows.
我洗地板的时候，你可以擦窗户（while含有对比的意思）
He had learned English for three years before he went to London.
他去伦敦之前已学了三年英语。
After the children had gone to bed, she began to prepare her lessons.
孩子睡觉了以后她开始备课。
It is just a month since we arrived here.
我们到这儿刚刚一月。
He waited until / till we finished our meal.
他一直等到我们吃完饭。
Hardly had I gone to bed when the telephone rang.
我刚一上床，电话就响了。
注意：
as和when、while：
as, when 引导短暂性动作的动词。当从句的动作发生于主句动作之前，只能用when 引导这个从句，不可用as 或 while。从句表示"随时间推移"连词能用as，不用when 或while。while只可表示"段时间",从句谓语只限于延续性动词。从句谓语表示状态时,通常用while。当主从句之间表示转折或对比关系时，多用while, 不用as或when。
表示先时或后时，即主句的谓语动作发生在从句之前或之后，主要连词有：after（在……之后）, before（在……之前）, when（=after）等。
Until和till：通常与短暂动词的否定式连用（not…till/until）通Until可用于句首，而till通常不用于句首。
hardly…when，no sooner…than引导的状语从句要倒装。
⑵有一些表示时间的名词短语也可用来引导时间状语从句：the minute, the moment, every time, the first time
例：
The moment he reached the country, he started his search.
他一到达这个国家，就开始他的探寻工作。
Every time I went to his house, he was out.
我每次去他家，他都出去了。
⑶有一些表示时间的副词也可用来引导时间状语从句：
Directly，immediately, instantly
例：
Directly the master came in, everyone was quiet.
校长一进来， 大家就安静下来。
She burst into tears she had got the bad news.
她一听到这个坏消息立即就哭了。
2）地点状语从句
地点状语从句是由where（在……的地方）, wherever（无论哪里）引导的：where，表示某一个；wherever，表示任何一个。
Where there is a will, there is a way.
有志者，事竟成。
You’d better make a mark where you have any questions.
哪儿有问题，你最好在哪儿做个记号。
He would keep in touch with us wherever he was.
他无论在什么地方，总是与我们保持联系。
Wherever I am I will be thinking of you.
不管我在哪里我都会想到你。
3）原因状语从句
表示原因的状语从句可以由as（由于）, because（因为）, since（既然）, now （that）（既然）, considering that（顾及到）, seeing that（由于）等连词引导，如：
I missed the train because I got up late.
由于我起晚了，所以错过了火车。
Since the weather is getting warmer, you had better put off your sweater.
由于天气渐暖，你最好脱去你的毛衣。
As he was not well, I decided to go there without him.
由于他身体不好，我决定不到他去那里。
It must have rained last night, for the ground is wet.
昨晚一定下雨了，地面是湿的。
Considering how young he was, we all think it’s not suitable for him to be the CEO.
考虑到他年轻了，我们都认为他不适合当首席执行官。
注意区别：because和since、for、as、now that：
because语势最强，用来说明人所不知的原因，回答why提出的问题。当原因是显而易见的或已为人们所知，就用as或 since。由because引导的从句如果放在句末，且前面有逗号，则可以用for来代替。但如果不是说明直接原因，而是多种情况加以推断，就只能用for。now that都表示“既然”now that一定要是现在发生的，since可以是现在，也可以是过去和现在。
4） 目的状语从句
引导目的状语从句的主要连词有:that, so that（以便）, in order that（为了）, for fear that（以便）, in case（万一）等，从句中常常使用一些情态动词，如：can, could, may, might, should等。如：
Let’s take the front seats （so） that we may see more clearly.
我们坐前排吧，这样我们看得更清楚些。
She studied harder in order that the she might pass the final exam.
她学习更加刻苦为了通过期末考试。
Tom took the address down for fear that（lest） he should forget it.
汤姆把地址写下省得忘了。
Better take more clothes in case the weather is cold.
最好多带些衣服以防天气会冷。
5） 结果状语从句
引导结果状语从句的连词有：
that, so that（从句中不带情态动词）, so…that（如此……以致……）, such…that（如此……以致……）等。
"so"and"such"
such 是形容词，修饰名词或名词词组，so 是副词，只能修饰形容词或副词。 so 还可与表示数量的形容词many, few, much, little连用，形成固定搭配。
so foolish such a fool
so nice a flower such a nice flower
so many / few flowers such nice flowers
so much / little money such rapid progress
so many people such a lot of people
（ so many 已成固定搭配，a lot of 虽相当于 many，但 a lot of 为名词性的，只能用such搭配。）
"so … that" and" such… that
So…that与such…that之间的转换既为 so与such之间的转换。
The girl is so beautiful that everyone likes her.
she is such a beautiful girl that everyone likes her.
⑴so...that结构在某种情况下可以与enough to和too...to结构相互转换。例如:
She is so short that she can’t reach the buttons of the lift. =She is too short to reach the buttons of the lift.
⑵so that也可以引导结果状语从句,意为“结果是;以至于”。例如:
They missed the bus so that they were late for class.
注:so that也可引导目的状语从句,此时可用to或in order to替换,将其改为简单句。例如:
He got up early so that he could get to school on time. =He got up early to get to school on time. =In order to get to school on time,he got up early.
6）条件状语从句
表示条件的状语从句可以由if（如果）, unless（除非）, in case（万一）, so /as long as（只要）, as/ so far as（就……而言）, on condition that（条件是……）, suppose（假设）, supposing（假设）（仅用在问句中）等词或词组引导。一般情况下当主句是将来时的时候，从句要用一般现在时。如果表示过去将来的情况，就用一般过去时。
As/So long as they don’t lose heart, they’ll find a way to overcome the difficulty.只要他们不灰心，他们就能找到克服困难的方法。
Ring us in case you have any difficulty.
万一你有什么困难，请给我们打电话。
If one doesn’t respect himself, he can’t expect others to respect him.
如果一个人不自尊，就无法期望别人尊重他。
We’ll let you use the room on condition that you keep it clean and tidy.
只要你能保持整洁，我们可以让你使用这个房间。
As/So far as I know, he is an excellent artist.
据我所知，他是一个优秀的艺术家。
He’ll accept the job unless the salary is too low.
他会接受这项工作的，除非薪水太少。
Suppose/Supposing we can’t get enough water, what shall we do?
假设我们弄不到足够的水，那我们怎么办？
"if"and"unless"
一般情况下，unless相当于if…not，可以互换。如：
I won’t let you in unless you show me your pass = I won’t let you in if you don’t show me your pass.如果你不出示通行证，我就不让你进来。
但是，在下列情况下，两者是有区别的。
⑴unless引导真实条件句，if…not可以引导真实条件句或非真实条件句。
⑵unless从句中有否定词时，不能换成if…not结构。
⑶如果主句描述的是情感或情绪活动方面的内容，if…not结构不能换成unless。
如：I’ll be quite glad if she doesn’t come this evening.
她今晚如果不来我很高兴。
⑷unless表示唯一条件，不能用and连接重复使用，if…not则可以。
7）方式状语从句
⑴方式状语从句通常由as, （just） as…so…, as if, as though引导。
as, （just） as…so…引导的方式状语从句通常位于主句后，但在（just） as…so…结构中位于句首，这时as从句带有比喻的含义，意思是"正如…"，"就像"，多用于正式文体，例如：
Always do to the others as you would be done by.
你希望人家怎样待你，你就要怎样待人。
As water is to fish, so air is to man.
我们离不开空气，犹如鱼儿离不开水。
Just as we sweep our rooms, so we should sweep backward ideas from our minds.
正如打扫房屋一样，我们也要扫除我们头脑中落后的东西。
⑵as if, as though
两者的意义和用法相同，引出的状语从句谓语多用虚拟语气，表示与事实相反，有时也用陈述语气，表示所说情况是事实或实现的可能性较大。汉译常作"仿佛……似的"，"好像……似的"，例如：
They completely ignore these facts as if （as though） they never existed.
他们完全忽略了这些事实，就仿佛它不存在似的。（与事实相反，谓语用虚拟语气。）
He looks as if （as though） he had been hit by lighting.
他那样子就像被雷击了似的。（与事实相反，谓语用虚拟语气。）
It looks as if the weather may pick up very soon.
看来天气很快就会好起来。（实现的可能性较大，谓语用陈述语气。）
说明：as if / as though也可以引导一个分词短语、不定式短语或无动词短语，例如：
He stared at me as if seeing me for first time.
他目不转睛地看着我，就像第一次看见我似的。
He cleared his throat as if to say something.
他清了清嗓子，像要说什么似的。
The waves dashed on the rocks as if in anger.
波涛冲击着岩石，好像很愤怒。
8）比较状语从句
比较状语从句常由than（比）, as（与……一样）等词引导：
It snows more heavily in Shenyang than in Xi’an.
沈阳下的雪比西安的大。
He is as tall as Tom.
他和汤姆一样高。
The result was not as/so good as I had expected.
结果不如我预料的那么好。
The busier he is, the happier he feels.
他越忙越开心。
9）让步状语从句
让步状语从句由although（尽管）, though（尽管）, however（无论怎样）, whatever（无论什么）, whoever（无论谁）, whomever（无论谁）, whichever（无论哪个）, whenever（无论何时）, wherever（无论哪里）, whether（是否）, no matter （who, what, where, when, etc）（无论……）, even if（即使）, even though（即使）等词引导。如：
We won’t be discouraged even if（=even though） we fail ten times.
我们就是失败十次也不泄气。
当有though, although时，后面的从句不能有but，但是 though 和yet可连用
It was an exciting game, though / although our team failed.
那是一场精彩的球赛，尽管我们队失败了。
Though the sore be healed, yet a scar may remain.
伤口虽愈合，但伤疤留下了。
Whether you believe it or not, it’s true.不管你信不信，这是真的。
However （=No matter how） expensive it may be, I’ll take it.
无论它有多贵，我也要买下它。
Don’t let them in, whoever （=no matter who） they are.
不管他们是谁，别让他们进来。
No matter what I say or how I say it, he always thinks I’m wrong.
无论我说什么或怎么说，他总认为是我错。
连词as也可以引导让步状语从句，但从句中要用特殊语序。如：
Young as he is, he knows a lot=Though he is young 或Young though he is, he….
他虽然年轻，但懂得很多。（though 也有这种用法，可以替换as,但although没有这种用法）
though还可以用作副词，放在句末。如：
It was hard work; I enjoyed it, though=It was hard work, but I enjoyed it.
那工作很苦，但是我喜欢干.
几个要注意的问题：
⑴从句用一般时态代替将来时态。不仅时间、条件状语从句，有时方式、让步状语从句也不用将来时。
⑵since的特殊用法：
since+瞬间动词过去式（从该动作发生时算起）
since+持续性动词过去式（从该动作结束时算起）：
It’s three years since he joined the army.
他参军三年了。
It’s three years since he was a soldier.
他退役三年了。
⑶有些表示时间、地点、条件、方式或让步等的状语从句中，如果谓语含有动词be，主语又和主句中的主语一致，或者主语是it，常把从句中的主语和谓语的一部分（特别是动词be）省略掉。例如：
Look out for cars when crossing the street（= when you are crossing …）
过街时当心车辆。
She hurriedly left the room as though /if angry （= as though/if she was /were angry…）
她急匆匆地走出屋去，好像很生气的样子。
If possible, I’d like to have two copies if it （= if it is possible,…）.
可能的话，我想要两本。
She advised me not to say anything unless asked （= unless I was asked ）
她劝我别说什么，除非有人要我说。
As a young man, he studied law and became a lawyer （= As/ When he was a young man,…）.他年轻时就学了法律，并当了律师。
⑷有时，the time（当……的时刻）, the moment（当……的时刻）, by the time（到……时候为止）, next time（下次）, the first time（第一次……的时候）, the last time（上次……的时候），immediately（一……就……）, instantly（一……就……）, directly（一……就……）等词或词组以及hardly /scarcely…when…（刚……就……）, no sooner…than…（刚……就……）等关联词也可引导表示时间的状语从句，例如：
Be sure to call on us next time you come to town.
下次你进城一定来看我们。
By the time he was fourteen, Einstein had learned advanced mathematics all by himself.
（by意为“到．．．．．．为止”，引起的从句中为一般过去时，主句中用过去完成时）
爱因斯坦到十四岁时就自学完了高等数学。
She rushed into the room immediately / the moment she heard the noise.
她一听到这声音，就冲进房间。
He left me a good impression the first time I met him.
我第一次见他时，他给我留下了好印象。
He had no sooner arrived there than he fell ill.
他刚到达那里就生起病来。
He had hardly finished when someone rose to refute his points.
他还没全说完，就有人起来反驳他的论点。
She had scarcely fallen asleep when a knock at the door awakened her.
她刚要睡着，忽然敲门的声音把她惊醒。
当hardly, scarcely, no sooner位于引起的句子的开头时，常用倒装语序。上面的例句可以依次改写成：
No sooner had he arrived there than he fell ill.
Hardly had he finished when someone rose to refute his points.
Scarcely had she fallen asleep when a knock at the door awakened her.
值得一提的是，这三组关联词引起的句子中，前面常用过去完成时，后面用一般过去时。
⑸表示"一…就…"的结构
hardly/scarcely…when/before, no sooner…than 和as soon as都可以表示"一…就…"的意思，例：
I had hardly / scarcely got home when it began to rain.
I had no sooner got home than it began to rain.
As soon as I got home, it began to rain.
注意：如果hardly, scarcely 或no sooner置于句首，句子必须用倒装结构：
Hardly / Scarcely had I got home when it began to rain.
No sooner had I got home than it began to rain.
我刚到家，就开始下雨了。