同位语一个名词(或其它形式)对另一个名词或代词进行修饰，限定或说明，这个名词(或其它形式)就是同位语。
同位语与被它限定的词的格要一致，并常常紧挨在一起。
1. 名词作同位语Mr. Wang, my child’s teacher, will be visiting us on Tuesday.2.短语作同位语I, the oldest girl in the family, always had to care for the other children.3. 直接引语作同位语But now the question comes to their minds, “Did she die young because she was a clone?”但是现在他们不得不思考这样的问题：“多莉早死是因为它是一只克隆羊吗？”4. 句子作同位语The girls were surprised at the fact that ocean ships can sail up the Great lakes.巨大的海轮可以开到五大湖，让表姐妹俩感到吃惊。
同位语从句用法一、同位语从句在句中的位置1. 在复合句中用作同位语的从句叫同位语从句。
它一般跟在某些名词后面，用以说明该名词表示的具体容。
(如news，idea，fact，promise，question，doubt，thought，hope，message，suggestion，words（消息），possibility等) I’ve come from Mr. Wang with a message that he won’t be able to see you this afternoon.我从王先生那边得知一个消息，他说他今天下午不能来看你了。
I heard the news that our team had won．我听到了我们队获胜的消息。
注：在名词doubt“怀疑”后的同位语从句用whether连接；在no doubt“不怀疑”之后的同位语从句用that连接。
We have some doubt whether they can complete the task on time.我们怀疑他们是否能准时完成任务。
There is no doubt that Zhang Wei will keep his promise. 我们相信卫会守信的。
2.有时同位语从句可以不紧跟在它所说明的名词后，而被别的词语隔开，在语法上叫做分隔式同位语从句。
The thought came to her that maybe she had left the door open when she left home. 她突然想起可能在她离开家时没把门关上。
The thought came to him that maybe the enemy had fled the city．他突然想起可能敌人已经逃出城了。
A warm thought suddenly came to me that I might use the pocket money to buy some flowers for my mother's birthday由于that从句太长，为避免句子失去平衡，此处用了间隔同位语从句二、同位语从句的引导词英语中引导同位语从句的词通有连词(that，whether), 连接代词(what, who, whom, whose, which), 连接副词(how, when, where)等。
（注：if, which 不能引导同位语从句。
）1. 连词that引导同位语从句（注：引导同位语从句的that不能省略）The idea that you can do this work well without thinking is quite wrong.你认为不动脑筋就能做好这件工作的想法是完全错误的。
（that从句作idea的同位语）【注1】在某些名词(如demand, wish, suggestion, resolution等)后面的同位语从句要用虚拟语气(should)+动词原形。
There was a suggestion that Brown should be dropped from the team.【注2】引导同位语从句的连词that通常不省略，但在非正式文体中也可以省去。
He grabbed his suitcase and gave the impression he was boarding the Tokyo plane. 他拿起了手提箱，给人的印象是他要登上飞往东京的飞机了。
2. 连词whether引导同位语从句（注：if不能引导同位语从句）The question whether we should call in a specialist was answered by the family doctor. 我们是否请专家由家庭医生来定。
He must answer the question whether he agrees to it or not.他必须回答他是否同意这样一个问题。
3.连接代词what, who, whom, whose, which引导同位语从句I have no idea what size shoes she wears.我不知道她穿几号的鞋。
I have no idea which wine is best—it’s a matter of personal taste.我不知道哪种酒最好，这是个人口味的问题。
The question who will take his place is still not clear.4.连接副词when, where, how, why 引导同位语从句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。
My original question, why he did it at all, has not been answered.三、同位语从句前名词的数同位语从句前的名词通常用单数形式，并且往往带有限定词(word除外)加以修饰。
Where did you get the idea that I could not come？你在哪儿听说我不能来？四、同位语从句与定语从句的的语法区别1．意义的不同同位语从句是用于说明所修饰名词的具体容的，它与被修饰词语通常可以划等号；而定语从句是限制所修饰名词的，它的作用是将所修饰的名词与其他类似的东西区别开来：We are glad at the news that he will come. 听到他要来这个消息我们很高兴。
(news的容就是that he will come，故that引导的是同位语从句)We are glad at the news that he told us. 听到他告诉我们的这个消息我们很高兴。
(that从句是限制the news的容的，即我们高兴只是因为他告诉的这个news而不是其他的news，故that从句为定语从句)2. 引导词的不同what, how, if, whatever 等可引导名词性从句，但不引导定语从句。
3. 引导词的功能上的不同that引导同位语从句时，它不充当句子成分，而引导定语从句时，它作为关系代词，要么充当定语从句的主语，要么充当定语从句的宾语。
如上例thathe told us中的that就充当told的宾语。
五、补充1.代词it可用作同位语从句的先行词。
这个it常放在某些动词或短语动词后作宾语，同时兼作其后that同位语从句的先行词。
I owe it to you that I am still alive. 幸亏你，我现在还活着。
有的语法学家把先行词it后的that从句看作是动词或介词的真正宾语。
一般认为，这种it后的that 从句应看作it的同位语，因为它相当于“主语+be+表语”结构。
You must se to it that the children don't catch cold. (=You must see to it, andIt is that the children don't catch cold.)你要当心，别让孩子们着凉了。
2.短语及固定句式后的同位语从句I will come on condition that John is invited.如果约翰也被邀请的话，我就来。
简析：短语On condition, on supposition, on the ground(s), on the understanding, with the exception, in spite of the fact, on the assumption及句式There be + no doubt (hope, chance, possibility,…)后的that从句为同位语从句。
练习一用适当的连接词填空：It worried her a bit _____ her hair was turning gray.2.I have no idea _____ we can do with these waste materials.3.____the doctor really doubts is____my mother will recover from theserious disease soon.4.It is hoped____nature will never be destroyed.5.____do you guess will give a talk on English tomorrow?6.-- I drove to Zhuhai for the air show last week.-- Is that ____ you had a few days off?7. Word came____I was wanted at the office.8.Do you know ____of them will be our new headmaster?9.The teacher didn’t tell me ____we were wrong.10. It’s generally considered unwise to give a child ____he or she wants.B.单项选择It was true _____ Alice did surprised her mother.A. thatB. whatC. that, whatD. what, that2. Does ____matter much ____he can’t come t o the meeting.A. it, ifB. that, ifC. it, whetherD. this, whether3.--What are you anxious about?-- ____A. How can we succeedB. Whether we can succeedC. When can we succeedD. That we can succeed4.The reason ____the little actress has been such a success is ____she is both clever and hard-working.A. why, whyB. why, thatC. that, becauseD. for, because5. ____leaves the room last ought to turn off the lights.A. WhoB. WhoeverC. AnyoneD. The person6.I really don’t know _____I had this photo taken.A. where it was thatB. it was thatC. where it wasD. it was why7.? Dr. Black comes from either Oxford or Cambridge. I can’t remember ____.A. whereB. thereC. whichD. that8.--What do you think of China?--____different life is today from ____it used to be.A. How, whatB. What, whatC. How, thatD. What, that9.Give this to ____you think can do the work well.A. whoB. whomC. whoeverD. whomever10.____troubles me is ____I can’t learn all these English idioms by heart.A. That, thatB. What, whatC. That, whatD. What, that答案A. 1. that 2. what 3. what, whether 4. that 5. who 6. why7. that 8. which 9. where 10. whateverB. 1—5 CABBB 6—10 ACACD练习二1.The fact ____ she works hard is well known to us all.A.thatB.whatC.whyD.which2.The fact ____ he was successful proves his ability.A.thatB.whatC.whichD.why3.The news ____ he was kidnapped surprised us greatly.A.whatB.thatC.whyD.when4.His suggestion ____ the meeting be delayed was turned down.A.whichB.thatC./D.it5.I have no idea ____ he will start.A.whenB.thatC.whatD./6.I've come from the government with a message ____ the meeting won't be held tomorrow.A.ifB.thatC.whetherD.which7.The thought ____ he might fail in the exam worried him.A.whenB.whichC.whatD.that8.The order ____ the prisoner be set free arrived too late.A.whichB.whetherC.thatD.what9.The nurses are trying their best to reduce the patient's fear ____ he would die of the disease.A.thatB.asC.of whichD.which10.He often asked me the question ____ the work was worth doing.A.whetherB.whereC.thatD.when1-5 AABBA 6-10 BDCAA。