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高考英语专题复习
专题二 虚拟语气、定语从句、名词性从句
目 录
一、虚拟语气 2
（一）if 条件句 2
1.基本用法 2
2.虚拟条件句的省略 2
3.混合条件句 3
4.含蓄条件句 3
（二）Should 型虚拟语气 3
1.基本用法 3
2.注意事项 4
（三）其他虚拟语气 5
1.wish 的用法 5
2.as if /as though 的用法 5
3.would rather 的用法 5
4.两个句型 6
二、定语从句 7
（一）认识定语从句 7
1.定语从句的概念 7
2.定语从句的分类 7
（二）定语从句的关系词 8
1.关系代词引导的定语从句 8
2.关系副词引导的定语从句 9
3.关系代词与关系副词的选择 10
4.定语从句选择题做题方法 10
（三）特殊用法 11
三、名词性从句 17
（一）认识名词性从句 17
1.名词性从句的概念 17
2.名词性从句常用关联词 17
3.名词性从句的分类 18
（二）主语从句 19
（三）宾语从句 22
1.宾语从句概念 22
2.由关联词 that 引导的宾语从句 22
（四）表语从句 24
（五）同位语从句 25
一、虚拟语气
（一）if 条件句
1.基本用法
类别 用法 例句
If引导的条件从句 与现在事实相反 从句动词：过去式（be用were） 主句动词：should/would/could/might +动词原形 If he were here，he would help us.
与过去事实相反 从句动词：had+过去分词 主句动词：should/would/could/might +have+过去分词 If I had been free，I would have visited you.
与将来事实相反 从句动词：过去式/should+动词原形/ were+不定式 主句动词：should/would/could/might +动词原形 If it should rain tomorrow，we would not go camping.
2.虚拟条件句的省略
虚拟条件句的从句部分如果含有were，should， 或had，可将if省略，再把were，should 或had 移到从句句首.实行部分倒装。例如：
If they were here now， they could help us.
= Were they here now， they could help us.
如果他们现在在这里，他们就能帮助我们。
If it should rain， the crops would be saved.
= Should it rain， the crops would be saved.
如果下雨，庄稼就能保收。
3.混合条件句
主句与从句的动作发生在不同的时间，这时主、从句谓语动词的虚拟语气形式因时间不同而不同，这叫做混合条件句。
规则：无论是主句还是从句，与什么时间相反，就用与这个时间相对应的句型。
If it had rained last night（ 从句与过去事实相反，从句用过去完成时），it would be very cold today（主句与现在事实相反，主句用情态动词+动词原形） .
4.含蓄条件句
在某些虚拟语气结构中没有if条件句，虚拟条件是用其它形式表示出来，这种现象在语 法上称为“含蓄条件句”。含蓄条件通常分为以下几种情况：
通过without 的介词短语表示条件。例如：
Without air，there would be no living things.
=If there were no air，there would be no living things.
通过but for介词短语表达条件。例如：
But for the rain I would have arrived much earlier.
=If it had not been for the rain，I would have arrived much earlier.
通过连词otherwise（or）表达条件。例如：
She came to town yesterday，otherwise I would not have met her. = If she hadn't come to town yesterday，I would not have met her.
（二）Should 型虚拟语气
1.基本用法
在表示“建议”、“要求”、“命令”或“应当做……"”等意义的动词后面的宾语从句、表语从句和 同位语从句中的谓语动词需要用虚拟语气，即用“ （should）+ 动词原形”来表示。
口诀：I DROP CAPS.
常用的动词是：insist坚持；demand 要求；desire要求；decide 决定；request 请求；require 需要、要求；order 命令； propose 建议；command 命令；ask 请求；arrange 安排；advise 建议；prefer宁愿；suggest 建议。
例句巩固
I insisted that he should come with us.
The committee decided that no one should be admitted.
I proposed that we should start early.
She suggested that I should save some money.
2.注意事项
这些动词变为被动语态（如：It is suggested+that 主语从句）形式后，从句的谓语动词仍用“ （should）+ 动词原形”。
It is ordered that the medicine should be sent soon.
It has been desired that the meeting should be postponed till next week.
由这些动词派生的或转换的名词（如 ：decision 决定；demand 要求；suggestion 建议；requirement 要求、需要）后面的从句的谓语动词仍用 “ （should）+ 动词原形”。
My suggestion is that we should send a few people to help the other groups.
这些动词在不表达“某事必须做或某事重要”这一词义时（如：suggest 暗示、表明； insist 坚决认为），后面的宾语从句则不用虚拟语气，而用陈述语气。
She suggested（建议） that they should start early.
她建议他们应该早点开始。
Her smile suggested （表明） that she was satisfied.
她的微笑表明她很满意。
（三）其他虚拟语气
Wish 用法， as if/as though 用法， would rather 用法两个句型。
1.wish 的用法
宾语从句动作发生时间 宾语从句时态 例句
对现在的希望 一般过去时（be动词用were） I wish I were as tall as you.
对过去的希望 过去完成时 I wish I had met her yesterday.
对将来的希望 过去将来时 I wish it would rain tomorrow.
2.as if /as though 的用法
as if引导的从句动作先后 as if引导从句时态 例句
对现在的虚拟 一般过去时（be动词用were） He looks as if he were an artist.
对过去的虚拟 过去完成时 She speaks English so fluently as if she had studied English in America.
对将来的虚拟 过去将来时 She learns English so hard as if she would go to America next year.
3.would rather 的用法
would rather引导的从句动作先后 would rather 引导从句时态 例句
对现在或将来的 虚拟 一般过去时 I would rather they didn't come tomorrow.
对过去的虚拟 过去完成时 I would rather I hadn't seen the movie yesterday.
4.两个句型
It is（high）time that 从句 （从句用过去式或should+动原，should不可省）
过去式 It is time that the children went to bed.
Should+动词原形 It is high time that the children should go to bed.
二、定语从句
先行词 关系代词 关系副词 限制性/非限制性
（一）认识定语从句
1.定语从句的概念
★修饰某一名词或代词的从句叫定语从句。定语从句一般跟在它所修饰的先行词之后。
★先行词：被定语从句修饰的词叫先行词。
★关系词：引导定语从句的词叫关系词。
如：
The man who is shaking hands with my father is a policeman.
The man先行词 who 关系词
who is shaking hands with my father 定语从句
【定语从句例句】
Football is a game which is liked by most boys.
I visited a scientist whose name is known all over the country.
Tomorrow I will bring the magazine that you asked for.
Her brother，who is now a soldier，always encourages her to go to college.
★关系词
关系代词：that，which，who，whom，whose，as；
关系副词：when，where，why。
★关系词的作用
·引导定语从句
·代替先行词
·在定语从句中担当 一个成分
2.定语从句的分类
定语从句可分为限制性定语从句和非限制性定语从句。
（1）限制性定语从句：全句不可分割的一部分，如果把它去掉，句子意思便会受到影响，从句前不用逗号。
China is a country which has a long history.
中国是一个历史悠久的国家。
（2）非限制性定语从句：此从句只是对所修饰的名词作进一步的补充，即便省去，全句的意思并不受影响。一般用逗号和主句分开。
China，which was founded in 1949，is becoming more and more powerful.
中国在1949年成立，现在变得越来越强大。
★限制性定语从句举例
The teacher told me that Tom was the only person that I could depend on.
老师告诉我，汤姆是我唯一可以依靠的人。
In the street I saw a man who was from Africa.
在街上，我看见一个非洲人。
★非限制性定语从句举例
His mother， who loves him very much，is strict with him.
他母亲非常爱他，对他很严厉。
Last summer I visited the People's Great Hall，in which many important meetings are held every year.
去年夏天，我参观了人民大会堂，这里每年都会举行许多重要会议。
（二）定语从句的关系词
关系代词 关系副词 介词+关系代词
that as/which where way/time
1.关系代词引导的定语从句
关系代词 作用 例句
who 指人 在定语从句中 作主语 The boys who are running are from Class One. Yesterday I helped a child who had lost his way.
whom 指人 在定语从句中作 宾语，常省略 Mr.Li is the person（whom）you talked about. Li Ming is just the boy（whom）I want to see.
which 指物 在定语从句中 作主语或宾语， 做宾语时常可省略。 Football is a game which is liked by most boys. This is the pen（which）he bought yesterday.
that 指人=who /whom; 指物=which在定语从句中作主语或宾语，作宾语时常可省略。 The person that/whom you introduced to me is very kind. Yesterday I received a letter that/which came from Australia.
whose 通常指人，也可指物，在定语从句中作定语。 I visited a scientist whose name is known all over the country. He has a friend whose father is a doctor.
as Such...as; the same…as 在定语从句中作主语，表语或宾语。 I should like to use the same tool as you used yesterday. As is known to everybody，the moon travels round the earth once every month.
2.关系副词引导的定语从句
关系副词 作用 例句
when 指时间， 在定语从句中 作时间状语。 I still remember the day when I first came to this school. The time when we got together finally arrived.
where 指地点， 在定语从句中 作地点状语。 Shanghai is the city where I was born. The house where I lived ten years ago has been rebuilt.
why 指原因， 在定语从句中 作原因状语。 Please tell me the reason why you missed the plane. The reason why he was punished is unknown to us.
3.关系代词与关系副词的选择
①从句缺少主要成分→关系代词
充当主语·who which that
充当宾语·whom which that。
充当定语·whose
②从句不缺少主要成分→关系副词
指时间·when
指地点·where
指原因·why
③关系代词与关系副词的选择：
I know a place where we can have a picnic.关系副词在从句中充当地点状语
I know a place which /that is famous for its beautiful natural scenery .关系代词在从句中充当主语
I will never forget the days when we spent our holidays together.关系副词充当状语
I will never forget the days that/which we spent together.关系代词在从句中充当宾语
This is the reason why he was dismissed.关系副词在从句中充当原因状语
This is the reason that/which he explained to me for his not attending the meeting.关系代词在从句中充当宾语
4.定语从句选择题做题方法
①找先行词
②把先行词放入引导词位置，查看其在从句中做什么成分
③根据先行词性质，在从句中做的成分来选择引导词
The lady _________ came to see us last week is my mother's friend.
The lady came to see us.先行词在从句中作主语，指人，所以用who
Beijing is the place _______I was born.
I was born in the place.先行词在从句中作地点状语，所以用in which或where
（三）特殊用法
介词+关系代词 that/which as/which where way/time
1.关系代词在定语从句中作介词宾语时，从句常常由“介词十关系代词”引出。
The school（which /that）he once studied in is very famous.
→The school in which he once studied is very famous.
This is the boy（whom/who /that）I played tennis with yesterday.
→This is the boy with whom I played tennis with yesterday.
The manager whose company I work in pays much attention to improving our working conditions.
→The manager in whose company I work pays much attention to improving our working conditions.
2.“介词+关系代词”引导的定语从句
“介词+关系代词”的用法：
★用法：in/on/at/ for+which =when/where/why 作时间，地点，原因状语
We'll never forget the time during which we worked together.
我们永远不会忘记我们一起工作的时间。
This was the bus stop at which（where）the accident happened.
这就是发生事故的公共汽车站。
★用法：介词+ which/whom/whose作目的，方式状语
Is this the car for which you paid a high price
这是你花高价买的那辆车吗？
The teacher with whom the students in our class are popular is Jone.
我们班学生最喜欢的老师是Jone。
★用法：名词/代词/数词+介词of+which/whom 做主语
I read some books， the covers of which are yellow with years.
我读了一些书，它们的封面已经因为年久而发黄。
Present at the meeting were almost experts on DNA，most of whom（=of whom most） came from the US.
出席会议的几乎都是DNA专家，其中大部分来自美国。
★用法: 介词+ which/ whom + to do 强调某一个名词，相当于一个简化的定语从句
Here is the money with which to buy a piano.
这是买钢琴的钱。
Nancy is the right person on whom to depend.
南希是值得信赖的人。
★用法:根据定语从句中动词或形容词等的习惯搭配来确定。根据与先行词搭配的具体意义来确定。根据所表达的意思来确定。
Education is the business to which the Smiths are devoted.
教育是史密斯夫妇所从事的事业。
I'll never forget the time during which I spent my childhood in the country.
我永远不会忘记在乡下度过的童年时光。
The colorless gas without which we cannot live is called oxygen.
没有氧气我们就无法生存。
3.含有介词的短语动词一般不坼开，介词仍放在短语动词的后面。
例： look for，look after，take care of等。
This is the watch（which/that）I am looking for.√
This is the watch for which i am looking. ×
The babies（whom/who/that）the nurse is looking after are very healthy.√
The babies after whom the nurse is looking are very healthy.×
4.若介词放在关系代词前，关系代词指人时只 可 用whom， 不可用who，that ; 关系代词指物时只可用 which，不可用that。 关系代词是所有格时用whose。
The man with whom you talked just now is my neighbor.√
The man with that who you talked just now is my neighbor. × The plane in which we flew to Canada was really comfortable.√
The plane in that we flew to Canada was really comfortable.×
5.“介词+关系代词”前还可有some，any，none，all，both，neither，many，most，each，few 等代词或者数词。
He loves his parents deeply，both of whom are very kind to him.
In the basket there are quite many apples， some of which have gone bad.
There are forty students in our class in all， most of whom are from big cities.
Up to now，he has written ten stories， three of which are about country life.
6.只用 that 不用which 的情况
当先行词是 everything，anything，nothing，something，all，none，few，little，some 等不定代词时，或当先行词受 every，any，all，some，no，little，few，much 等代词修饰时。 例：
Have you taken down everything that Mr.Li said
There seems to be nothing that is impossible to him in the world.
All that can be done has been done.
There is little that I can do for you.
He stayed in the library and looked up any information that they needed.
注意：当先行词指人时，偶尔也可用关系代词who。
例：Any man that/who has a sense of duty won't do such a thing.
All the guests that/who were invited to her wedding were important people.
当先行词被序数词或形容词最高级修饰修饰时。
例：The first place that they visited in London was the Big Ben.
This is the best film that I have ever seen.
当先行词被 the very，the only修饰时。
例：This is the very dictionary that I want to buy.
After the fire in his house，the old car is the only thing that he owns.
注意：当先行词指人时，偶尔也可用关系代词who。
例：Wang Hua is the only person in our school who will attend the meeting.
当先行词前面有who，which 等疑问代词时。
例：Who is the man that is standing by the gate
Which is the T-shirt that fits me most
当先行词为人与动物或人与物时。
例：They talked about the persons and things that they remembered at school .
Look at the man and his donkey that are walking up the street.
7.只用 which 不用 that 的情况
关系代词前有介词时。
Galileo built a telescope through which he could study the skies.
引导非限制性定语从句时。
Football，which is a very interesting game，is played all over the world.
先行词本身是that时。
What's that which flashed in the sky just now
先行词后有插入语时。
Here is the English grammar book which，as I've told you，will help improve your English.
8.先行词 as 和 which 引导的定语从句
as 和 which 引导非限制性定语从句时，其用法有相同之处，也有不同之处。具体情况是：
☆ as 和 which 都可以在定语从句中做主语或宾语，代表前面整个句子。
He married her，as/which was natural.
He is honest，as/which we can see.
但 as 只指代前面的句子，而 which 可以指代句子和单词。
Oct.1st，which is our National Day，is always celebrated with singing and dancing.
☆ as 引导的非限制性定语从句可以放在主句之前、主句之后，甚至还可以分割主句。which引导的非限制性定语从句只可放在主句之后。
As is known to all，China is a developing country.
Zhang Hua has been to Paris more than ten times，which/as I don't believe.
注意：当主句和从句之间存在着逻辑上的因果关系时，关系词往往只用which。
Tom was late for school again and again，which made his teacher very angry. These tables are made of metal，which made them very heavy.
☆非限制性定语从句中谓语为被动时，常用 as 作主语。
as is said/known/announced/reported/mentioned/expected/discussed等。 如：
As is known to all，Taiwan is part of China.
☆ as 引导非限制性定语从句，有“正如”的含义，which 无此含义，因此，下列句式中多用as:
as is well known as is known to all
as has been said before as has been already pointed
as is expected/hoped/supposed as we all can see
as is often the case
☆当先行词受 such，the same 修饰时（限制性），关系词常用as。
I've never heard such stories as he tells.
我从未听过他讲过这样的故事。
He is not such a fool as he looks.
他看上去并不愚笨。
This is the same dictionary as I lost last week.
这和我上周丢失的那本词典是一样的。
注意：当先行词受the same 修饰时，偶尔也用 that 引导定语从句，但与as 引导的定语从句意思有区别。
She wore the same dress that she wore at Mary's wedding. （同一件裙子）
She wore the same dress as her younger sister wore. （类似的裙子）
9.关系副词 where 的用法补充
在定语从句中，当先行词为表示“环境、状况、情境”等意思的抽象名词时，关系副词可以使用 where.
先行词 例句
point You reach a point where medicine can't help. We have reached a point where a change is needed.
case There are cases where the word“mighty”is used as an adverb. Let's discuss a number of cases where beginners of English fail to use the language properly.
situation He got into a situation where it is hard to decide what is right and wrong. If you risk something important，you cause it to be in a dangerous situation where you might lose it.
position It's put me in a position where I can't afford to take the job
job She wants a job where her management skills can be put to good use I don't want a job where I'm chained to a desk all day.
10.关系词 way 和 time 后接定语从句的情况
☆当先行词是way （意为“方式，方法”），关系词在定语从句中作状语时，引导定语从句的 关系词有以下三种方式：
What surprised me was not what he said but the way in which he said it.
What surprised me was not what he said but the way that he said it.
What surprised me was not what he said but the way （不填） he said it.
☆先行词是time 时，若time 作“次数”讲，应用关系代词 that 引导定语从句，that 可省 略；若time 作“一段时间、时代”讲，应用关系副词when 或介词at/during which 引 导定语从句。
This is the second time （that）the President has visited the country.
I can hardly remember how many times（that）I've failed.
三、名词性从句
（一）认识名词性从句
1.名词性从句的概念
在复合句中具有名词作用并做主语，表语，宾语和同位语的从句叫名词性从句 （Noun Clauses）。 名词从句的功能相当于名词词组，根据它在句中不同的语法功能，名词从句又可分别称 为主语从句、宾语从句、表语从句和同位语从句。
2.名词性从句常用关联词
连接词 词义 功能
that 无词义 不作成分，只起连接作用
whether/if 是否 不作成分，只起连接作用
what，which 什么，哪个 作主语、宾语、表语
who，whom，whose 谁，谁的 作主语、宾语、定语
when，where，how，why 什么时候/地方， 怎么样，为什么 作状语
how many/much 多少 作定语
how soon/often/ long/much 多久，多久一次， 多长，多么 作状语
Whatever =anything that 无论什么 作主语、宾语、 表语、定语
Whoever =anyone who 无论谁 作主语
Whomever=anyone whom 无论谁 作宾语
Whosever =anyone whose 无论谁的 作定语
Whichever =anyone that 无论哪个 作宾语、定语、 主语、表语
3.名词性从句的分类
种类 作用 例句
主语从句 在复合句中作主语，相当于名词，一般置谓语之前，也可用it作形式主语，主语从句放主句之后 Whether he will come or not doesn't matter much. Whoever comes here will be welcome.
表语从句 在复合句中作表语，相当于名词，位于系动词之后 It looks as if it is going to snow.
宾语从句 在复合句中作宾语，相当于名词 He asked me which team could win the game.
同位语从句 放在名词之后（news，idea，advice，fact等）表明其具体内容 You have no idea how worried we are. The fact that he lied again greatly surprised us.
（二）主语从句
在句中起主语作用的从句称为主语从句。
主语从句通常由从属连词 that，whether，f 和连接代词 what，who，which， whatever，whoever 以及连接副词 how，when，where，why 等词引导。
that 在句中无词义，只起连接作用，不能省略；
That the college will take in more new students is true.
whether 引导的主语从句。whether 在从句中不作任何成分，只起连接作用，不能省略，表 示“是否”。
Whether the work can be completed on time is doubtful.
（可改为 It is doubtful whether the work can be completed on time.）
Whether you can succeed or not depends on how hard you work at it.
连接代词和连接副词在句中既保留自己的疑问含义、又起连接作用，在从句中充当从句的成分。
What he wants to tell us is not clear.
他要跟我们说什么，还不清楚。
Who will win the match is still unknown.
谁能赢得这场比赛还不得而知。
It is known to us how he became a writer.
我们都知道他是如何成为一名作家的。
Where the English evening will be held has not yet been announced.
英语晚会将在哪里举行，还没有宣布。
whether 与if 均有“是否”的意思。但在下列情况下，whether 不能被if替代：
① whether 引导主语从句（位于句首）、表语从句或同位语从句时
Whether he can come to the party on time depends on the traffic.
他是否能控时来参加聚会要看交通状况。（主语从句）
The question is whether we can get in touch with her.
问题是我们能否和她取得联系。（表语从句）
I have no idea whether the meeting will be held.
我不知道会议是否要举行。（同位语从句）
② whether 引导的从句作介词宾语时
I'm thinking about whether I should quit my present job.
我正在考虑是否应该辞去现在的工作。
③后紧跟不定式时
He seemed undecided whether to go or stay.
他似乎还没有决定去留。
④ 后紧跟 or not 时
It remains to be seen whether or not this idea can be put into practice.
这一想法能否付诸实践还有待观察。
⑤位于discuss后引导宾语从句时
They are discussing whether the meeting will be put off.
他们正在讨论会议是否会被推迟。
that 从句作主语时，常用it作形式主语，that 引导真正的主语从句后置，常见的句式主要有如下几种：
necessary必要的 certain明确的 natural自然的
right 正确 clear清晰的 obvious明显的
important 重要的 possible可能的 likely可能的
unlikely不可能的 strange奇怪的
① It+ 系动词+形容词+that 从句。
常用于这种结构的形容词有：
It is obvious that you've made a big mistake.
很明显你犯了一个大错。
It is likely that he can't come to the meeting.
很可能他不来参加会议了。
It is fortunate that I have passed the driving test.
很幸运我通过了驾驶考试。
“It is necessary/important/surprising/strange/unthinkable/
unbelievable/incredible+that从句”结构中，从句中谓语常用“ should+动词原形”形式，其中 should可省略。
It is necessary that a college student（should）master one or two foreign languages.
大学生掌握一两门外语是必要的。
② It+ 系动词+名词+that 从句。
常用于这种结构的名词有：
a pity 遗憾 an honor荣耀
no wonder 难怪 no surprise不奇怪
fact 事实 wonder 奇迹
a shame 令人遗憾的事 good news 好消息
It is a pity that you didn't attend the lecture yesterday.
你昨天没参加讲座真是遗憾。
It's no wonder that you've achieved so much success.难怪你取得了这么大成功。
It is common knowledge that the earth turns around the sun.
地球围绕着太阳转是常识。
③ It+be+ 过去分词+that 从句。
常用于这种结构的过去分词形式有：
said 据说 told告诉
suggested 建议 decided 作出决定
remembered 记得 thought 认为
considered 认为 well-known 很著名
heard 听说 ordered 根据命令
announced 据宣布 reported 据报道
advised 建议 hoped 希望
It is said that the professor has already succeeded in carrying out this experiment.
据说这位教授已经成功地完成了这项实验。
It is reported that no passengers were injured in the accident.
据报道在事故中没有乘客受伤。
It is generally considered that boys are better at science than girls.
人们普遍认为男孩比女孩更擅长理科。
④ It+动词（+宾语或状语）+that从句。
常用于这种结构的动词有：
It happened that I was away when he called.
他打电话时，我正好不在家。
It turns out that our team has won the game.
结果是我们队赢了这场比赛。
It occurred to me that we should get in touch with the manager.
我突然想起来我们应该与经理联系。
"It+be+ suggested/advised/ordered/requested/ insisted
/demanded+that 从句 ”
结构中，that 以从句中谓语应用“ should+ 动词原形”， should 可省略。
It is suggested that you （should） spend more time in studying English.
建议你花更多的时间学习英语。
（三）宾语从句
1.宾语从句概念
在句中作宾语的从句叫宾语从句。引导宾语从句的关联词与引导主语从句表语从句的关联 词大致一样，在句中可以作谓语动词或介词及非谓语动词的宾语。
2.由关联词 that 引导的宾语从句
由连接词 that 引导宾语从句时，that 在句中不担任任何成分，在口语或非正式的文体中 常被省去，但如从句是并列句时，第二个分句前的 that 不可省。例如：
He has told me （that） he will go to Shanghai tomorrow.
他告诉我（他）明天要去上海。
We must never think that we are good in everything while others are good in nothing.
我们决不能认为我们是好的，而别人是不好的。
注意：在demand、order、suggest、decide、insist，desire，request，command 等表示要求、命令、建议、决定等意义的动词后，宾语从句常用“（should）+ 动词原形”。
例如 ：
I insist that she （should）do her work alone.
The commander ordered that troops （should）set off at once.
3.用 who，whom，which，whose，what，when，where，why，how，whoever，whatever，whichever 等关联词引导的宾语从句相当于特殊疑问句，应注意句子语序要用陈述语序。
I want to know what he has told you.
我想知道他告诉了你什么。
She always thinks of how she can work well.
她总在考虑怎样才能工作得更好。
She will give whoever needs help a warm support.
她会给需要帮助的人一个温暖的支持。
4.think，believe，imagine，suppose 等动词引起的否定性宾语从句中，要把上述主句中的动 词变为否定式。即将从句中的否定形式移到主句中。
We don't think you are here.
我们认为你不在这。
I don't believe he will do so.
我相信他不会这样做。
5.注意宾语从句中的时态呼应，当主句动词是现在时，从句根据自身的句子情况，而使用不同时态。
①主句谓语动词如果是一般现在时，从句谓语动词可用任何所需要的时态。
I know you don't know what I think at all.
我知道你根本不知道我想的是什么。
I know he didn't tell you that he would come then.
我知道他没告诉你他那时要来。
②主句谓语动词如果是一般过去时态，从句谓语动词一般要用过去的某种时态。 He told me that he had told Mary about the meeting already.
他告诉我他已经把会议的事告诉了玛丽。
6.宾语从句时态的特殊情况
如果主句中的动词时态是过去时，宾语从句表达的是科学真理或自然规律的内容，那么从句的时态不受主句限制，还是用一般现在时。
·The teacher told us that the earth goes around the sun.
有时尽管主句中的时态是过去时，但宾语从句中有绝对的过去时间状语，此时从句用用一般过去时（而不是过去完成时）。
·She told me that she bought a computer in 2005.
宾语从句的语乞词wish，suggest，advise，order，insist 等后接虚拟语气的宾语从句，见“虚拟语气”专题。
（四）表语从句
☆在句中作表语的从句叫表语从句。
☆引导表语从句的关联词与引导主语从句的关联词大致一样，表语从句位于连系动词后，有时 用as if引导。
☆从属连词 that 和 whether: 在从句中不作成分， that 无实义， whether 有“是否”之 意，均不能省略。
The reason for your mistake is that you lack confidence.
你犯错误的原因是你缺乏信心。
The question is whether we can reduce the cost of the product.
问题是，我们能否降低产品的成本。
☆其基本结构为：主语+系动词+that从句。
The fact is that we have lost the game.
事实是我们已经输了这场比赛。
That's just what I want.
这正是我想要的。
This is where our problem lies.
这就是我们的问题所在。
That is why he didn't come to the meeting.
那就是他为什么不到会的原因。
It looks as if it is going to rain.
看上去天要下雨了。
☆需要注意的，当主语是reason时，表语从句要用that引导而不是because。
The reason why he was late was that he missed the train by one minute this morning.
他之所以迟到，是因为今天早上他错过一班火车。
【注意】 whether 可引导表语从句，但与之同义的if 却通常不用于引导表语从句。
☆表语从句中的虚拟语气
如果主句的主语是 advice，proposal，recommendation，suggestion，order，command， request，requirement 名词时，表语从句的谓语应用虚拟语气，即无论主语 是单数或复数，谓语一律用“（should+） 动词原形”的形式。
The proposal of the UN is that a peace-keeping force （should）be sent to the area.
联合国的建议是向这个地区派驻维和部队。
☆常见句型：A is to B what C is to D. A 对于B 就像C 对于D 一 样。
Engines are to machines what hearts are to animals.
发动机对于机器犹如心脏对于动物一样。
（五）同位语从句
☆同位语从句是用以解释说明某一名词内容和实质的从句。
☆同位语从句通常由 that 引导，可用于同位语从句的名词有 advice、demand、doubt、fact、hope、idea、information、message、news、order、problem、promise、 question、request、suggestion、truth、wish、word 等。
The news that we won the game is exciting.
我们赢得这场比赛的消息令人激动。
I have no idea when he will come back home.
我不知道他什么时候回来。
The thought came to him that Mary had probably fallen ill.
他想到可能玛丽生病了 。
☆常用的引导词有：that，whether，where，how，when 等。if 一般不连接同位语从句。 that，whether 不 作 成 分 ，whether 表示“是否”，其他连接词具有实义，同时在同位语从句 中作一定成分。同位语从句的引导词一般都不省略。

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