同位语从句语法填空
同位语从句专项讲解及练习含答案
同位语从句。
1. 同位语从句定义。
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/先行词后面，用以说明该名词/先行词表示的具体内容。
2. 同位语从句的名词/先行词。
A．可以跟同位语从句的名词/先行词通常有news，idea，fact，promise，question，doubt，thought，hope，message，suggestion，words（消息），possibility等（一般的“抽象”名词都可用）。
Eg：I’ve come from Mr wang with a message that he won’t be able to see you this afternoon．我从王先生那里来，他让我告诉你他今天下午不能来看你了。
B. 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Eg：There was a suggestion that Brown should be dropped from the team.有一项建议是布朗应该离队。
C．有时同位语从句可以不紧跟在说明的名词/先行词后面，而被别的词隔开。
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。
3. 同位语从句的引导词。
A.连词that引导，引导同位语从句的that不能省略，which不能引导同位语从句。
Eg：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。
B. 连词whether引导，if不能引导同位语从句。
Eg：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。
备考2023年高考英语一轮复习27：同位语从句
备考2023年高考英语一轮复习27：同位语从句一、单选题(共20题；共40分)1．（2分）The question came up at the meeting ______ we had enough money to conduct the research.A．what B．which C．that D．whether2．（2分）In fact, more than one account suggests that ______ Newton was certainly inspired by a falling apple, there is no proof ____ it hit him on the head.A．when, why B．while, that C．if, that D．while, why3．（2分）Many experts hold the view _________ teacher development is _________ the key to better education lies.A．which; where B．that; in whichC．that; where D．that; what4．（2分）The manager put forward a suggestion ________ we _________ an assistant. There is too much work to do.A．whether; should have B．what; hadC．that; should have D．which; had5．（2分）News came ________ she was chosen as one of the nurses to go to Wuhan to help in the fight against COVID-19.A．how B．why C．what D．that6．（2分）A story goes ________ Elizabeth I of England liked nothing more than being surrounded by clever and qualified noblemen at court.A．when B．where C．what D．that7．（2分）David left word with my secretary ________ he would call on me in the afternoon.A．who B．that C．where D．which8．（2分）In fact, more than one account suggests that________.A．there, on no account, is proof that the falling apple hit Newton on the headB．on no account should there be proof whether the falling apple hit Newton on the headC．on no account is there proof whether the falling apple hit Newton on the headD．there, on no account, should be proof that the falling apple hit Newton on the head9．（2分）________ surprised me most was the news ________ our team won.A．That; that B．What; which C．What; that D．That; which10．（2分）The manager put forward a suggestion ________ we should have an assistant. There is too much time on it.A．whether B．that C．which D．what11．（2分）His success was because of _________ he had been working hard.A．that B．the fact that C．the fact which D．the fact12．（2分）The proposal Father made this morning did sound feasible ______________ every member of the family ______________ one-third of his or her income in case of emergency.A．which, set aside B．that, set asideC．which, sets aside D．that, sets aside13．（2分）I've come from the government with a message ________ the meeting won't be held tomorrow.A．if B．that C．whether D．which14．（2分）All the scientists on the meeting believed that there was no doubt ______ a cure for SARS would be found.A．which B．that C．what D．whether15．（2分）There is no doubt _______he will come tomorrow, but I do doubt _____he will come on time.A．that; that B．that; whetherC．whether; whether D．whether; that16．（2分）There can be no doubt ____________teachers love hardworking students.A．where B．that C．which D．whether17．（2分）One of the men gave his opinion ___________ the book said was right.A．that what B．that C．what D．whether18．（2分）His promotion was due to ______________he had been working hard.A．that B．what C．the fact which D．the fact that19．（2分）We all share his belief________ true craftwork is treasure________ can last beyond life time.A．which; that B．that; what C．what; which D．that; that20．（2分）The beauty of rereading lies in the idea _____ our bond with the work is based on our present mental register.A．what B．which C．that D．how二、语法填空(共20题；共22分)21．（1分）The idea is a driver with a valid driving licence in his own country can drive freely in another country without going through another driving test.22．（1分）I have no idea happened to him.23．（1分）I made a promise to myself this year, my first year in high school, would be different. （填连接词）24．（1分）A thought came to me he might be in the library.25．（1分）Much of the value of mistakes comes from the fact they demand a cost that must be paid.26．（1分）Scientists have obtained more evidence plastic is finding its way into the human body.27．（1分）There is some doubt he is willing to attend the meeting on behalf of our community.28．（2分）The specialist expressed his hope he would visit China again the next year, and that was the very hope he expressed as soon as he arrived in the country.29．（1分）More and more people have come to see the fact China is no longer what she used to be.30．（1分）The boss has no idea the assistant has got in mind, but he is eager to find out. 31．（1分）The question we can preserve the heritage site from being ruined has been bothering me recently.32．（1分）He is always strict with himself in the hope he can come up to the high standard required for a teacher.33．（1分）They asked her the question she was late for the meeting.34．（1分）When checking my email, I found a message I'd gotten the chance to take part in the spelling bee, which made me surprised and excited.35．（1分）There is great possibility he will lose his temper if she keeps finding fault with him. 36．（1分）We are not interested in the question they will be able to help us.37．（1分）There is growing evidence staying up late at night has a serious impact on people's health.38．（2分）Fears grew the number of deaths could reach 5, according to figures (release) by emergency services.39．（1分）I always keep the belief in mind I can succeed through hard work.40．（1分）There can be little doubt he will make the mistake again.答案解析部分1．【答案】D【解析】【分析】句意：是否我们有足够的的钱来实施这项研究，这个问题在会议上提了出来。
高中英语同位语从句练习(含解析)
同位语从句练习一、语法填空1.The fact ______________ the money was gone does not mean it was stolen.2.I'm sorry to hear the awful news ________________ your brother died at a young age.3.We have some doubt ___________ he can win the first prize.4.Most importantly, you should always hold the belief__________you are sure to succeed as long as you keep your direction all the time.5.The fact I was a foreigner was a big disadvantage.6.We all agree with the idea we should make most of our time to study.7.When I heard the news ___________ our team had won, I burst into tears.8.The manager put forward a suggestion__________we should have an assistant.There is too much work to do .9.According to the professor, the question __________ it is right or wrong depends on the final result of the experiment.10.I am in favor of the view we must make full use of the existing technical equipment.11.Is there any possibility _________ their team will win in the final?12.Word came __________ the astronomers had taken the first ever image of a black hole, which is located in a distant galaxy.13.There’s no doubt _____________ she will run out of money very soon if she spends like this.14.The possibility__________there is life on other planets in the universe has always inspired scientists to explore the outer space. 15.The patient’s son asked the doctor the question__________his father could survive the big operation.二、单句改错：1.The fact whether man has landed on the moon is true.2.She expresses her hope whether she will come and visit China again.3.I could no longer ignore the fact what he was unhappy.4.Dad made a promise he would buy me a new iPad if I passed the English test.5.There is no doubt whether teachers play an important role in children’s growth.6.The news they had won the game soon spread over the whole school.7.However, we can’t overlook the fact it must be operated with aphone and a network.8.The news which he won the first prize is true.9.Many children are not aware of the fact which life is hard for their parents.10.We are glad at the news the headmaster will join us in hiking this Sunday.11.There is no doubt if English has become a universal language nowadays.12.We shared the belief what if you’re fortunate enough to have success, you should put something back.13.The news which my brother failed to win the speech contest is really disappointed.14.Finally I want to express my hope which all the young fellows can make full use of time, because time and tide wait for no man. 15.There is a popular belief among parents who schools don’t pay any attention to handwriting.同位语从句参考答案语法填空：1.答案：that解析：考查同位语从句。
同位语从句及练习题(含答案)
同位语从句一、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内容。
如：1. 我听到了我们队获胜的消息。
I heard the news _________ our team had won．2. 我不知道你在这里。
I had no idea ___________ you were here．二、可以跟同位语从句的名词通常有news，idea，fact，promise，question，doubt，thought，hope，message，suggestion，words（消息），possibility等。
如：我从王先生那里来，他让我告诉你他今天下午不能来看你了。
3. I’ve come from Mr Wang with a message ____________ he won’t be able to see you this afternoon．三、英语中引导同位语从句的词通有连词that, whether，连接副词how, when, where等。
（注：if, which不能引导同位语从句。
）如：4. 我不知道他什么时候回来。
I have no idea __________ he will be back．5. 他必须回答他是否同意这样一个问题。
He must answer the question ___________ he agrees to it or not.四、有时同位语从句可以不紧跟在说明的名词后面，而被别的词隔开。
如：6. 几年以后，有消息传来说拿破仑要亲自视察他们。
Several years later，word came __________ Napoleon himself was coming to inspect them．7. 他突然想起可能敌人已经逃出城了。
The thought came to him __________ maybe the enemy had fled the city．五、同位语从句与定语从句的区别。
同位语从句讲解及练习含答案
一、理解同位语从句的含义，把握同位语从句的实质在主从复合句中作同位语的从句称为同位语从句。
同位语从句一般用that, whether，what, which, who, when, where, why, how 等词引导，常放在fact, news, idea, truth, hope, problem, information, wish,promise, answer, evidence, report, explanation, suggestion, conclusion等抽象名词后面，说明该名词的具体内容。
换言之，同位语从句和所修饰的名词在内容上为同一关系，对其内容作进一步说明。
The news that they had won the game soon spread over the whole school.他们比赛获胜的消息很快传遍了整个学校。
析：they had won the game说明The news的全部内容，因此该句为同位语从句。
二、正确运用同位语从句的引导词，准确把握同位语从句1.如同位语从句意义完整，应用that引导同位语从句。
（即that 不充当任何成分，只起连接作用，不可省略）The general gave the order that the soldiers should cross the river at once.将军下达了战士们立即过河的命令。
析：the soldiers should cross the river at once是the order的全部内容，且意义完整，因此应用that引导同位语从句。
We heard the news that our team had won. 我们听到消息说我们队赢了。
They were worried over the fact that you were sick. 他们为你生病发愁。
The news that we are having a holiday tomorrow is not true. 明天放假的消息不实。
高三英语同位语从句的特点完形填空题80题
高三英语同位语从句的特点完形填空题80题1The Importance of EducationEducation is crucial for personal growth and development. It opens doors to new opportunities and helps people achieve their dreams. One of the most important aspects of education is learning different subjects. For example, mathematics helps us develop logical thinking, while literature enriches our imagination.In high school, students are exposed to a wide range of subjects. Some students are passionate about science and dream of becoming scientists. Others are interested in history and want to explore the past.1. The fact that students have different interests shows that education should be ___.A. diverseB. difficultC. boringD. easy答案：A。
解析：“The fact that students have different interests”这个同位语从句表明学生有不同的兴趣，所以教育应该是多样化的，diverse。
B 选项“difficult”困难的；C 选项“boring”无聊的；D 选项“easy”容易的，均不符合语境。
高中英语语法填空考点总结归纳
高中英语语法填空考点总结归纳高中英语语法填空部分是考察学生对英语语法知识的掌握程度和运用能力的重要环节。
下面将对高中英语语法填空考点进行总结归纳，帮助学生更好地应对这一考试环节。
一、名词性从句名词性从句在语法填空中出现频率较高，主要考察学生对名词性从句引导词的运用和从句的结构掌握。
1. 主语从句：引导词为that、whether、if。
例：It is uncertain _______ he will come to the party.答案：whether/if2. 宾语从句：引导词为that、whether、if。
例：He asked me _______ I could help him with his homework.答案：whether/if3. 表语从句：引导词为that。
例：The fact _______ he is a doctor surprises me.答案：that4. 同位语从句：引导词为that。
例：I have no doubt _______ he will win the game.答案：that二、固定搭配语法填空中常考固定搭配，特别是动词、形容词和名词的搭配。
1. 动词搭配：考察常用动词的固定搭配，如go for a walk, take a shower, make a decision等。
例：She often _______ for a walk after dinner.答案：goes2. 形容词搭配：考察常用形容词的固定搭配，如be keen on, be aware of, be familiar with等。
例：She is _______ playing tennis.答案：keen on3. 名词搭配：考察常用名词的搭配，如take measures, do research, make progress等。
例：We should _______ to protect the environment.答案：take measures三、时态和语态时态和语态是语法填空考察的重点内容，主要考察学生对时态和语态的正确运用。
（完整版）高中-同位语从句详细讲解与练习（附答案）
（完整版）高中-同位语从句详细讲解与练习（附答案）同位语从句讲义1．定义：用作同位语的从句叫做同位语从句。
2.用法：同位语从句的先行词多为fact, news, idea, thought, question, reply, report, remark等，关联词多用从属连词。
如：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 I could not come?你在哪儿听说我不能来？Early in the day came the news that Germany had declared war on Russia.德国已对俄国宣战的消息一大早就传来了。
注：同位语从句偶尔由从属连词whether引导。
如：I have no idea whether he’ll come or not.我不知道他是否来。
连接代词who, which, what和连接副词where,when, why, how 亦可引导同位语从句。
The question who should do the work requires consideration.谁该干这项工作，这个问题需要考虑。
W e 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。
1．that引导的同位语从句与定语从句之区别?that引导的同位语从句that引导的定语从句句法功能上that只起连接从句的作用，无意义。
在从句中不充当句子成分。
高中英语同位语从句形式完形填空题60题
高中英语同位语从句形式完形填空题60题1The discovery of penicillin is one of the most important events in medical history. It was discovered by Alexander Fleming in 1928. Fleming noticed that a certain mold had grown on a culture plate and that the bacteria around the mold had been destroyed. This led him to believe that the mold must produce a substance that could kill bacteria.He began to study the mold and eventually isolated the active ingredient, which he named penicillin. The discovery of penicillin had a profound impact on medicine. It led to the development of antibiotics and saved countless lives.1. The fact that Fleming discovered penicillin is widely known. The discovery was a result of his careful observation and scientific curiosity. The fact ___ he was able to isolate the active ingredient was also crucial.A. thatB. whichC. whenD. where答案：A。
高中英语重点句型——同位语从句专项练习(知识点+习题解析)
英语句型同位语从句专项练习（知识点+习题解析）定义：同位语表示与之同位的名词(短语)的实际内容，对前面的名词(短语)加以补充说明或进一步解释。
Definition：An appositive clause explains a noun, or shows the meaning ofa noun.例句：1．The suggestion that we should develop the natural resources in the region has been discussed.关于我们应该开发本地区资源的建议已经讨论过了。
2．The idea that we asked Mike to come yesterday is quite good.昨天我们请迈克来，这个主意太好了。
3．The fact that the earth moves around the sun is known to all.地球围绕太阳转，这个事实人人皆知。
4．We have a doubt whether it is true.我们怀疑那是不是真的。
5．The text tells us a fact that smoking does great harm to people's health .这篇课文又告诉我们一个事实，吸烟对健康危害很大。
6．The idea that he we could ask the teacher for advice is wonderful.我们可以向老师请教，这个主意不错。
同位语从句的连接词1.引导同位语从句的连接词最常见的是that。
2. 连接词when, where, why, whether, how 等也可引导同位语从句。
例如：Have you any idea how fast sound travels? 你知道声音传播有多快吗？This is some doubt whether he will come. 他是否会来还不一定呢。
同位语从句
同位语从句一、 同位语1. 定义：同位语是句子成分的一种，它位于名词、代词后面，说明它们的性质和情况，它可以由名词、代词、数词、名词性短语或从句充当。
2. 同位语的表现形式：1） 名词、代词、数词等在句中作同位语。
I lived with my aunt Anna.(名词)He wants to buy a shirt, one that is not expensive but nice.。
（代词） She is the oldest among them six.(数词)2） 名词短语、形容词短语、动名词短语、不定式短语作同位语。
Is this your purpose, to avoid being punished? (不定式短语)Professor Smith, a football fan, often watches football games on TV.(名词短语) 3） 同位语从句在句中作同位语He told me the news that the president had been murdered.(从句)二、 同位语从句1.定义：在复合句中充当同位语的从句叫“同位语从句”。
它一般跟在某些抽象名词的后面，用于说明该名词表示的具体内容。
常见的这类名词有 news, fact, idea, thought, promise, suggestion, order, 等。
2.引导词|：1） 连词：that, whether2） 连接副词：when/where/why/how /whenever/wherever/however3） 连接代词：what/who/whom/whose/which/whatever/whoever/whomever/whosever/whichever三、同位语从句与定语从句的区别：1. 先行词： 同位语从句的先行词是抽象名词；定语从句的先行词是具体、抽象名词或代词。
2023年高中英语语法之同位语从句的考点归纳及专项训练
2023年高中英语语法之同位语从句的考点归纳及专项训练同位语从句的结构（一）由that引导I have no doubt that he will overcome all this difficulties.他会克服一切困难，对此我并不感到怀疑。
【特别提示】：同位语从句引导词that不可省略。
（二）由whether引导The question whether we need more time to do the work has not been decided.我们是否需要更多时间来做这项工作，这个问题还未决定。
（三）由其他词引导的同位语从句I have not made up my mind what elective subjects I am to take next term.我还没有决定好下学期上哪些选修课。
When you are about halfway through the story, try to make a guess how the plot will develop.当你把故事读到一半时，猜测一下情节将如何发展。
I have no idea when I will be back from Shanghai.我不知道我什么时候从上海回来。
（四）同位语从句与被修饰名词的分割有时，为了保持句式的平衡，将同谓语从句与被修饰的名词分割，其间出现其他成分。
Concerns were raised that witnesses might be encouraged to exaggerate their stories in court to ensure guilty verdicts.人们日益担心，证人可能会因此而受到鼓励，在法庭上夸大事实（这里先行词concerns与that 以保证陪审团对被告做出有罪的判决。
同位语从句被谓语were raised隔开。
）同位语从句的引导词运用1.that引导同位语从句。
完整版)高中-同位语从句详细讲解与练习(附答案)
完整版)高中-同位语从句详细讲解与练习(附答案)同位语从句是用作同位语的从句，通常用于解释或说明先行词。
常见的先行词有fact、news、idea、thought、n、reply、report、remark等。
连接同位语从句的从属连词多为that，有时也可以用whether。
例如：They were all very worried that you were sick。
这件事让他们都非常担心。
I have no idea whetherhe'll come or not。
我不知道他是否会来。
除了that之外，连接代词who、which、what和连接副词where、when、why、how也可以引导同位语从句。
例如：The n who should do the work requires ___。
谁该干这项工作，这个问题需要考虑。
___ where we are going to ___。
我们还没有决定去哪里度暑假的问题。
同位语从句与定语从句的区别在于，同位语从句只起连接从句的作用，没有实际意义，且不能省略连接词that。
而定语从句则起到限定作用，可以用关系代词who、which、that等引导，且连接词可以省略。
例如：The book that ___。
我昨天买的那本书很有趣。
同位语从句是指在复合句中作为同位语的从句，一般紧跟在某些名词后面，用以说明该名词表示的具体内容。
比较常用的名词有news，idea，fact，promise，n，doubt，thought，hope，message，n，words（消息），possibility等。
例如，I heard the news that our team had won.（我听到了我们队获胜的消息。
）同位语从句的引导词包括连词that，whether，连接代词和连接副词等。
在某些名词后面的同位语从句要用虚拟语气，如demand。
wish。
高考英语一轮复习《同位语从句》常考题解析
高考英语一轮复习27：同位语从句一、单选题1．The question came up at the meeting ______ we had enough money to conduct the research.A．what B．which C．that D．whether【分析】是否我们有足够的的钱来实施这项研究，这个问题在会议上提了出来。
空处引导同位语从句解释question。
根据句意，对于“我们是否有足够的钱”表示不确定。
whether为从句的引导词，意为“是否”，符合句意。
故选D。
2．In fact, more than one account suggests that ______ Newton was certainly inspired by a falling apple, there is no proof ____ it hit him on the head.A．when, why B．while, that C．if, that D．while, why【分析】事实上，不止一种说法表明，虽然牛顿确实是受到了一个掉落的苹果的启发，但没有证据表明它击中了他的头部。
结合句意可知，第一空是让步状语从句，表示“虽然，尽管”，用while引导；第二空引导同位语从句，对名词proof的内容补充说明，从句结构、意义完整，应用that引导，that在从句中不作任何成分，起连接作用。
故选B。
3．Many experts hold the view _________ teacher development is _________ the key to better education lies.A．which; where B．that; in whichC．that; where D．that; what【分析】很多专家认为，老师的发展就是更好教育的关键所在。
第一空是同位语从句，作view的同位语，对view进行解释说明，从句不缺成分，表达完整的含义，应用从属连词that；第二空是表语从句，从句中缺少lie的状语，应用where。
同位语从句——精选推荐
同位语从句同位语从句同位语从句⼀、同位语1.定义:同位语就是句⼦成分的⼀种,它位于名词、代词后⾯,说明它们的性质与情况,它可以由名词、代词、数词、名词性短语或从句充当。
2.同位语的表现形式:1）名词、代词、数词等在句中作同位语。
I lived with my aunt Anna、(名词)He wants to buy a shirt, one that is not expensive but nice、。
(代词)She is the oldest among them six、(数词)2）名词短语、形容词短语、动名词短语、不定式短语作同位语。
Is this your purpose, to avoid being punished? (不定式短语)Professor Smith, a football fan, often watches football games on TV、(名词短语)3）同位语从句在句中作同位语He told me the news that the president had been murdered、(从句)⼆、同位语从句1、定义:在复合句中充当同位语的从句叫“同位语从句”。
它⼀般跟在某些抽象名词的后⾯,⽤于说明该名词表⽰的具体内容。
常见的这类名词有news, fact, idea, thought, promise, suggestion, order,等。
2、引导词|:1）连词:that, whether2）连接副词:when/where/why/how /whenever/wherever/however3）连接代词:what/who/whom/whose/which/whatever/whoever/whomever/whosever/whichever三、同位语从句与定语从句的区别:1.先⾏词: 同位语从句的先⾏词就是抽象名词;定语从句的先⾏词就是具体、抽象名词或代词。
中考英语同位语从句高级用法完形填空题20题答案解析版
中考英语同位语从句高级用法完形填空题20题答案解析版1The world is full of people with different dreams and aspirations. Tom, a young boy, has a strong passion for music. He believes that music is the language of the soul. His dream is to become a famous musician one day. His friends also share his enthusiasm. They say that Tom has a real talent for music.Mary, on the other hand, is interested in science. She wants to be a scientist and discover new things. She is convinced that science can change the world. Her teachers often praise her for her curiosity and dedication.1. Tom's belief that music is the language of the soul is an example of a(n) ___ clause.A. thatB. whichC. whoD. what答案：A。
同位语从句通常用that 引导，解释说明前面抽象名词的内容。
这里“music is the language of the soul”是对“belief”的解释说明，所以用that。
选项B 中which 不能引导同位语从句；选项C 中who 通常用来引导定语从句修饰人；选项D 中what 不能引导同位语从句。
同位语从句及引导词
同位语从句及引导词同位语从句是名词性从句（主语从句、表语从句、宾语从句、同位语从句）的一种。
掌握同位语从句可以从以下几个方面入手：[同位语及充当同位语的形式]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。
单词、短语、直接引语以及从句都可以充当同位语。
1. 单词作同位语。
①This is my friend Harry.②We both come from Hunan.③We Chinese are brave and hardworking.④You three take these seats.这几个句子中Harry，both，Chinese和three都是同位语。
2. 短语作同位语。
①He says that Computertown UK was formed for just the opposite reason，to bring computers to people and make them “people-literate”.②Wang Li，just back from the training class，was madedirector of the Maternity Home.③People，old and young，took to the streets to watch the parade.这几个句子分别采用了不定式、介词短语和形容词作同位语。
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？”这个句子里则采用了直接引语来充当同位语。
[同位语从句及其位置]按照同位语的概念，同位语从句就是在复合句中充当同位语的名词性从句，用来表示与之同位的名词或名词短语的实际内容，或对前面的名词或名词短语加以补充说明。