定语从句和同位语从句的区别
一、 定语从句是形容词从句，其作用相当于一个形容词，是用来修饰前面的名词或代词的；同位语从句是名词从句，其作用相当于一个名词，是对前面的名词作进一步解释的。例如： 1． We heard the news that he had told her. 我们听到他对她说的消息。 2． We heard the news that he had won the game. 我们听到消息他赢得了比赛。 例1中的that从句的作用相当于一个形容词，其作用是修饰the news；例2中的that从句的作用相当于一个名词，是对the news的进一步说明。
二、定语从句的引导词在从句中充当一定的成分，可作主语、宾语、状语等；而同位语从句中的引导词在从句只起连接作用，不作任何句子成分。例如：
1. A plane is a machine that can fly. 飞机是一种能飞的机器。
2. The fact that they didn’t finish the work has to be faced. 必须面对事实，他们没有完成工作。
例1中的引导词that在从句中充当句子成分，作从句的主语，故为定语从句；例2中的that只起连接作用，引导从句解释fact的内容，不作任何句子成分，故为同位语从句。 三、引导定语从句的关联词在从句中作宾语或状语时，可以省略或被其他词代替；而同位语从句的引导词一般不能省略，更不能被代替。例如：
1. The news that she heard is true. 她听到的消息是真的。
2. The news that she will go abroad is true. 她将出国这消息是真的。 例1是定语从句，that可省略；例2是同位语从句，that不能省略。
3. The reason why he was chosen remains unknown. 他为什么被选上的原因还是不清楚。
4. The idea why he was chosen attracted our attention. 他为什么会被选上，这一想法引起我们的注意。
例3中why引导的是定语从句，why可以被 for which或 that 代替；例4中 why引导的是同位语从句，why 不能省去，也不能被其它词代替。
四、同位语从句与其所修饰的名词之间是一种同位关系，二者之间存在逻辑上的系表关系，可用“主+系+表”结构来表示。例如：
The news that he won the first place is true. 他赢得冠军的那个消息是真的。 上句若用“主+系+表”结构来表示，则是： The news is that he won the first place. 消息是他赢得了冠军。
意思合理，系表结构成立，故为同位语从句。
五、定语从句所修饰、限定的先行词可以是各类名词，可以有复数形式；而同位语从句一般都与抽象名词同位，一般没有复数形式。例如：
1. The possibilities that she was offered seemed very great.她得到的可能性似乎大些。
2. Her mother was worried about the possibility that her daughter dislike to go to school. 她的母亲很担心，她女儿有可能不喜欢上学。
例1中的possibilities是定语从句的先行词，可用复数形式；例2中的possibility是抽象名词，后接的是同位语从句，一般不用复数形式。
六、由when, why, where引导的定语从句分别修饰或说明表示时间、原因或地点的词，但它们引导的同位语从句一般不和表示时间或地点的词同位。例如：
1. I still remember the day when I first came to Beijing. 我仍然记得初次来北 京的那天。
2. I have no idea when she will be back. 我不知道她何时回来。
3. This is the house where I lived two years ago. 这是我两年前住的房子。 4. The question where we shall have a meeting hasn’t decided. 我们到什么地方去开会，这个问题没有决定。
例1、3中的when和 where引导的是定语从句，day 和house分别表示时间和地点；例2、4中的when和 where引导的是同位语从句。
同位语从句练习题
1.The fact ____ she works hard is well known to us all.
A.that B.what C.why D.which 2.The fact ____ he was successful proves his ability. A.that B.what C.which D.why
3.The news ____ he was kidnapped surprised us greatly. A. what B.that C.why D.when
4.His suggestion ____ the meeting be delayed was turned down. A.which B.that C./ D.it 5.I have no idea ____ he will start. A.when B.that C.what D./
6.I've come from the government with a message ____ the meeting won't be held tomorrow.
A.if B.that C.whether D.which 7.The thought ____ he might fail in the exam worried him. A.when B.which C.what D.that 8.The order ____ the prisoner be set free arrived too late. A.which B.whether C.that D.what
9.The nurses are trying their best to reduce the patient's fear ____ he would die of the disease.
A.that B.as C.of which D.which
10.He often asked me the question ____ the work was worth doing. A.whether B.where C.that D.when
名词性从句
一、语法知识 （一）, 主语从句
1, 由what等代词引导的从句,表示”所…的(东西)”,实际上等于一个现行词加上一个定语从句.也可以由-ever等代词引导.
What they are talking about is nothing valuable. What I really want is to have a good rest. Whatever she did is wrong.
Whoever passes the exam can get 50 yuan.
Whoever used to have another name raise your hand. 2, 由that引导的从句,通常用形式主语来代替. That he has disappeared worries his parents. It worries his parents that he has disappeared. It is not likely that he can win the lottery. It is a big surprise that he is still alive. 3, 由连接代词或连接副词或whether引导的从句. When she will be back is still a question. Where they had put the files troubled the spy. Whether he will take part in the play is clear. Whether or not she will go to Japan is up to her. （二）, 宾语从句
1, 由连接代词或副词引起的从句.
Please show me how to make him happy. I don’t know who did all the cleaning.
Have you decided whom you will take to Australia? She still wondered when she would leave school. I am wondering whether/if the dress is too short. He advised me which books I should read. 还可以做介词的宾语.
The singer still worries about where to live. The price depends on how many you will buy. 2, 由关系代词型what等代词引起的从句. I will tell you what I know.
We’ll give whatever help you need.
I plan to read whichever book you recommend. His father was not satisfied with what he had. She walked up to where I stood.
3, 由that引起的从句,在believe, think, suppose后常不加that.
在think, believe, suppose, expect等动词引起的宾语从句中,有时谓语尽管是否定意思,也只将前面的词否定. I don’t think you can beat me. He doesn’t expect we need worry.
有时在宾语和谓语之间可以插入一个间接宾语或状语. She reminded me that I had a meeting to attend.
They explained to us that they didn’t mean to make us angry.
有时在这种带有复合宾语的句子中, that引起的从句常常移到后面, 前面用一个it作为形式宾语.
I thought it very impossible that she would come. They took it for granted that the singer was coming. （三）, 表语从句是接在系动词后面的宾语从句.
（四）, 同位语从句, 在idea, fact rumor, news, hope, belief, thought, doubt等等词后面, 常常用that或连接代词或副词引导从句. I had no idea that they were in that plane.
He left me a message that he would buy me a ticket to the rock concert.
The news that we will have a one-month vacation is not true. 二、练习与检测
1. _____ we need more practice is quite clear. A. When B. What C. That D. /
2. _____ I accept the gift or refuse it is none of your business. A. If B. Whether
C. Even if D. No matter when
3. _____ knows the truth about it will tell you. A. Who that B. That C. Whoever D. That who
4. _____ he is doing seems quite difficult. A. How B. That C. Which D. What
5. _____ certain that his invention will lead to the development of production.
A. That’s B. This is C. It’s D. What’s
6. _____ that there is another good harvest this year. A. It says B. It is said
C. It was said D. He was said
7. _____ that she has received a doctor’s degree. A. It’s a splendid news B. This is a splendid news
C. It’s splendid news D. This is splendid news 8. It is strange _____.
A. that no one should like this book B. that no one liked this book C. that why no one likes this book D. why no one likes this book
9. It is suggested that the experiment _____ under low temperature. A. makes B. is make
C. should be made D. will be made 10. _____ still needs to be discussed. A. How is the plan to be carried out B. How the plan is to be carried out C. Why is the plan carried out D. Why the plan carried out 11. _____ is unknown to us all.
A. Where did she put it B. Where she put it C. That where she put it D. In which she put it 12. _____ nothing to do with us.
A. What he did is B. What he has done is
C. What did he do has D. What he has done has 13. That’s _____ the Party called on us to do. A. what B. that C. how D. why
14. She looked _____ she were ten years younger. A. that B. like C. as D. as though
15. The reason I have to go is _____ if I don’t. A. that she will be disappointed B. because she will be disappointed
C. on account of her being disappointed D. that she will be disappointing
16. It was _____ he worked hard that he succeeded. A. because B. since C. as D. for
17. It seemed that the girl _____.
A. had lost important something B. had lost something important C. lost important things D. lost something important 18. The fact _____ he is an advanced worker is well known. A. what B. which C. that D. why
19. The fact _____ in the past few years proves that our Party’s policy is correct.
A. that great achievement was made B. which great achievements were made
(完整word版)定语从句和同位语从句的区别
