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新人教版高中英语必修3Unit 5 The Value of Money-Listening &Speaking教学设计
Step 4: Listen again and decide if the following statements are true (T) or false (F).1 It was the first time Chen Liyan's story was reported. T口 F口2 Chen found 10,000 yuan in a small plastic bag in Taiyuan railway station口 F口3 Wang Zheng apologized to Chen because he couldn't offer her more money. T口 F口4 Chen took out a large loan to cure her daughter, T口 F口5 Wang set up a fundraising website for Chen's daughter after Chen told him about her situation. T口 F口Step 5：After listening, discuss the questions.1 What kind of person do you think Chen Liyan is?Chen Liyan is generous and honest because she returned a large sum of money to the owner.2 Did Chen return the money because she didn't need it?No. She returned the money because it was the right thing to do. Evidence for this is that she refused to accept the reward money because she felt that it had not been earned. 3 Is it common for people to do what Chen did?It depends on the culture. In some countries it is quite common to return money that has been found. In other countries, people believe "Finders are keepers!" 4 How did Wang Zheng feel about the return of his money?He must have been very happy and relieved to have gotten his money back. We know this because he thanked Chen repeatedly and even offered her a reward.5 Why did Ma Dongbao tell Wang about Chen's family?He must have had great sympathy for Chen and her daughter and wanted to help them.'We know this because he arranged help for them. 6 How did the news reporter feel about Chen's actions?The news reporter felt that it showed that money wasn't the most important thing in life. We know this because the reporter told us that this is what Chen believes. and then said, “that's a great attitude to take."
新人教版高中英语必修3Unit 5 The value of money-Reading and Thinking教学设计二
? Could you offer me some kind of work here?? I don’t want your charity, I just want an honest job.? Careless: I landed in Britain by accident.Step 7:Consolidation.? Find Henry? Roderick and Oliver were I .making a bet when they saw Henry, a poor young man. ? Know Henry? About a month ago, Henry was sailing and later he found himself carried out to sea by a strong wind. Fortunately, he 2.was spotted by a ship. And it was the ship that brought him to 3.England? Offer money to Henry ? Oliver and Roderick gave Henry a letter and told him that there was money in it. They 4.persuaded him to accept it, and made him 5.promise that it wouldn't be opened until 2 o'clock.Step 8：Language pointsa large amount of: a large quantity of; a great deal ofe.g. They bought a large amount of furniture before they moved their new house.make a bet: make an arrangement to risk money, etc. on an event of which the result is doubtful.e.g. We made a bet on the result of the match.permit sb to do something: allow somebody to do somethinge.g. My mother doesn’t permit me to ride in the street after it rained.by accident: as a result of chancee.g. I only found it by accident.stare at: look at somebody or something with the eyes wide open in a fixed gaze( in astonishment, wonder, fear, etc)to be honest: to tell you the truth; to be franke.g. To be honest, I don’t think we have a chance of winning.Step7 Homework:What do you think will happen to Henry? Will the bank-note help him or get him into trouble?
新人教版高中英语必修3Unit 5 The Value of Money-Reading and Thinking教学设计一
Everybody wants to get wealth.In today’s material world,making money or becoming wealthy symbolizes a person’s success and capability. Many people just make every effort, pay any price to attain greater wealth. With money,they can buy nice, large apartments in nice neighborhood. With money they can own luxurious cars. Wealth seems to bring all happiness in life.But is wealth the only road to happiness? Not really. There are many things in the world, which are beyond the means of money, such as friendship, love, health and knowledge. People are so preoccupied with struggling for money that they have no time or would not take the time to form or maintain friendship. What happiness can they feel living as lonely miserable creatures without love or friends in the world even if they accumulate tremendous wealth?In my opinion, people can’t do anything without money, but money is not everything. What money will bring you depends on your personal belief and goal in life. If you are kind enough to help others, especially the poor, money is a good thing to you. With it, you can do much more for the benefit of people and your country, and it will add to your own happiness. If you want money just for your own needs, you’ll never be satisfied or happy. In a word,you should have money spent for more people. Only then can money be the source of your happiness.Step 8 Homework4 students in a group, one acts Roderick, one Oliver, one servant and the fourth one acts Henry Adams, then listen to the tape, pay more attention to the difference between American English and British English in pronunciation, stress, tone.
新人教版高中英语必修3Unit 5 The Value of Money-Reading for Writing教学设计二
2. 您能看到, 我头发太长了。You can see that my hair is much too long.3. 无论什么时候, 只要您想回来就回来。Please come back whenever you want.4. 您仅有很少的头发要理! You only have too little hair to cut !5. 为您服务是我的荣幸！It is my honour to serve you!Step 9 Writing(Henry is walking down the street when he sees a sign for a place that cuts hair. He decides to have it cut. )H=Henry B=BarberH: Good afternoon, I’d like to have my hair cut, if I may. (The barber looks at Henry’s hair and continues cutting another man’s hair. ) Er, I’d really like a haircut. As you can see it’s much too long. B: (in a rude manner) Yes, I can see that. Indeed, I can. H: Fine, well, I’ll have a seat then. (He sits in one of the barber’s chairs. The barber turns to look at Henry. )B: It’s quite expensive here, you know! Are you sure you can afford it?H: Yes. I think so. (After his hair is cut, the barber tells Henry how much he must pay. Henry shows the barber the bank note. )B: Why Mr. . . (looks shocked)H: Adams. Henry Adams. I’m sorry. I don’t have any change. B: Please don’t worry! (wearing a big smile) Nothing to worry about! Nothing at all! Please come back whenever you want, even if you only have too little hair to cut! It will be my honour to serve you!Step 10 Pair workExchange drafts with a partner. Use this checklist to help your partner revise his/her draft.1. Are all the elements of a play included and in good order ?2. Do the character use suitable language ?3. Are the stage directions clear and useful ?4. Is the plot clear and exciting enough ?
新人教版高中英语必修3Unit 5 the value of money-Reading For Writing教学设计一
【参考范文】Narrator：(Henry is smiling as he leaves the restaurant. As he is walking down the street, he sees a sign for a place that cuts hair. He decides to get it cut. )H＝Henry；B＝Barber；R＝rude manH：Good afternoon, I'd like to get a cut, if I may. (The barber looks at Henry's hair and continues cutting another man's hair. )Er, I'd really like a haircut. As you can see it's much too long. B：(in a rude manner) Yes, I can see that. Indeed, I can. H：Fine, well I'll have a seat then. (He sits in one of the barber's chairs. The barber turns to look at Henry. )B：It's quite expensive here, you know！Are you sure you can afford it?H：Yes. I think so. (In comes the rude man. )R：Hey you there. I need a haircut quickly. Can you do me straightaway?B：All right, then, get in the chair and I'll see what I can do. R：Thank you. (sits down in one of the barber's chairs)H：Excuse me, but I was here first. Aren't you going to do my hair first?B：This man's in a hurry. H：Well so am I！I insist that you cut my hair first. B：OK, but I'll have to be quick. This gentleman is waiting. H：Thank you. (They both become quiet. After his hair is cut, the barber tells Henry how much he must pay. Henry shows the barber the bank note. )B：Why, Mr . . . (looks shocked)H：Adams. Henry Adams. I'm sorry, I don't have any change. R：You're that Mr Adams! Well，I'm glad I waited or I might never have known it was you. B：Why, Mr Adams, please don't worry！(wearing a big smile) Nothing to worry about！Nothing at all!Please come back any time, even if you only need too little hairs cut！It will be my honour to serve you!
新人教版高中英语选修2Unit 1 Science and Scientists-Discovering useful structures教学设计
The grammatical structure of this unit is predicative clause. Like object clause and subject clause, predicative clause is one of Nominal Clauses. The leading words of predicative clauses are that, what, how, what, where, as if, because, etc.The design of teaching activities aims to guide students to perceive the structural features of predicative clauses and think about their ideographic functions. Beyond that, students should be guided to use this grammar in the context apporpriately and flexibly.1. Enable the Ss to master the usage of the predicative clauses in this unit.2. Enable the Ss to use the predicative patterns flexibly.3. Train the Ss to apply some skills by doing the relevant exercises.1.Guide students to perceive the structural features of predicative clauses and think about their ideographic functions.2.Strengthen students' ability of using predicative clauses in context, but also cultivate their ability of text analysis and logical reasoning competence.Step1: Underline all the examples in the reading passage, where noun clauses are used as the predicative. Then state their meaning and functions.1) One theory was that bad air caused the disease.2) Another theory was that cholera was caused by an infection from germs in food or water.3) The truth was that the water from the Broad Street had been infected by waste.Sum up the rules of grammar:1. 以上黑体部分在句中作表语。2. 句1、2、3中的that在从句中不作成分，只起连接作用。 Step2: Review the basic components of predicative clauses1.Definition
新人教版高中英语选修2Unit 4 Journey Across a Vast Land教学设计
当孩子们由父母陪同时，他们才被允许进入这个运动场。3．过去分词(短语)作状语时的几种特殊情况(1)过去分词(短语)在句中作时间、条件、原因、让步状语时，相当于对应的时间、条件、原因及让步状语从句。Seen from the top of the mountain (＝When it is seen from the top of the mountain), the whole town looks more beautiful.从山顶上看，整个城市看起来更美了。Given ten more minutes (＝If we are given ten more minutes), we will finish the work perfectly.如果多给十分钟，我们会完美地完成这项工作。Greatly touched by his words (＝Because she was greatly touched by his words), she was full of tears.由于被他的话深深地感动，她满眼泪花。Warned of the storm (＝Though they were warned of the storm), the farmers were still working on the farm.尽管被警告了风暴的到来，但农民们仍在农场干活。(2)过去分词(短语)在句中作伴随、方式等状语时，可改为句子的并列谓语或改为并列分句。The teacher came into the room, followed by two students (＝and was followed by two students)．后面跟着两个学生，老师走进了房间。He spent the whole afternoon, accompanied by his mom(＝and was accompanied by his mom)．他由母亲陪着度过了一整个下午。
新人教版高中英语选修2Unit 1 Science and Scientists-Learning about Language教学设计
Step 7: complete the discourse according to the grammar rules.Cholera used to be one of the most 1.__________ (fear) diseases in the world. In the early 19th century, _2_________ an outbreak of cholera hit Europe, millions of people died. But neither its cause, 3__________ its cure was understood. A British doctor, John Snow, wanted to solve the problem and he knew that cholera would not be controlled _4_________ its cause was found. In general, there were two contradictory theories 5 __________ explained how cholera spread. The first suggested that bad air caused the disease. The second was that cholera was caused by an _6_________(infect) from germs in food or water. John Snow thought that the second theory was correct but he needed proof. So when another outbreak of cholera hit London in 1854, he began to investigate. Later, with all the evidence he _7_________ (gather), John Snow was able to announce that the pump water carried cholera germs. Therefore, he had the handle of the pump _8_________ (remove) so that it couldn't be used. Through his intervention，the disease was stopped in its tracks. What is more, John Snow found that some companies sold water from the River Thames that __9__________________ (pollute) by raw waste. The people who drank this water were much more likely _10_________ (get) cholera than those who drank pure or boiled water. Through John Snow's efforts, the _11_________ (threaten) of cholera around the world saw a substantial increase. Keys： 1.feared 2.when 3. nor 4.unless 5.that/which 6.infection 7.had gathered 8.removed 9.was polluted 10.to get 11. threat
新人教版高中英语选修2Unit 1 Science and Scientists-Reading and thinking教学设计
Step 5： After learning the text, discuss with your peers about the following questions:1.John Snow believed Idea 2 was right. How did he finally prove it?2. Do you think John Snow would have solved this problem without the map?3. Cholera is a 19th century disease. What disease do you think is similar to cholera today?SARS and Covid-19 because they are both deadly and fatally infectious, have an unknown cause and need serious public health care to solve them urgently.keys:1. John Snow finally proved his idea because he found an outbreak that was clearly related to cholera, collected information and was able to tie cases outside the area to the polluted water.2. No. The map helped John Snow organize his ideas. He was able to identify those households that had had many deaths and check their water-drinking habits. He identified those houses that had had no deaths and surveyed their drinking habits. The evidence clearly pointed to the polluted water being the cause.3. SARS and Covid-19 because they are both deadly and fatally infectious, have an unknown cause and need serious public health care to solve them urgently.Step 6: Consolidate what you have learned by filling in the blanks:John Snow was a well-known _1___ in London in the _2__ century. He wanted to find the _3_____ of cholera in order to help people ___4_____ it. In 1854 when a cholera __5__ London, he began to gather information. He ___6__ on a map ___7___ all the dead people had lived and he found that many people who had ___8____ (drink) the dirty water from the __9____ died. So he decided that the polluted water ___10____ cholera. He suggested that the ___11__ of all water supplies should be _12______ and new methods of dealing with ____13___ water be found. Finally, “King Cholera” was __14_____.Keys: 1. doctor 2. 19th 3.cause 4.infected with 5.hit 6.marked 7.where 8.drunk 9.pump 10.carried 11.source 12.examined 13.polluted 14.defeatedHomework: Retell the text after class and preview its language points
新人教版高中英语选修2Unit 1 Science and Scientists-Using langauge教学设计
This happens because the dish soap molecules have a strong negative charge, and the milk molecules have a strong positive charge. Like magnets, these molecules are attracted to each other, and so they appear to move around on the plate, taking the food coloring with them, making it look like the colors are quickly moving to escape from the soap.Listening text:? Judy: Oh, I'm so sorry that you were ill and couldn't come with us on our field trip. How are you feeling now? Better?? Bill: Much better, thanks. But how was it?? Judy: Wonderful! I especially liked an area of the museum called Light Games.it was really cool. They had a hall of mirrors where I could see myself reflected thousands of times!? Bill: A hall of mirrors can be a lot of fun. What else did they have?? Judy: Well, they had an experiment where we looked at a blue screen for a while, and then suddenly we could see tiny bright lights moving around on it. You'll never guess what those bright lights were!? Bill: Come on, tell me!? Judy: They were our own blood cells. For some reason, our eyes play tricks on us when we look at a blue screen, and we can see our own blood cells moving around like little lights! But there was another thing I liked better. I stood in front of a white light, and it cast different shadows of me in every color of the rainbow!? Bill: Oh, I wish I had been there. Tell me more!? Judy: Well, they had another area for sound. They had a giant piano keyboard that you could use your feet to play. But then, instead of playing the sounds of a piano, it played the voices of classical singers! Then they had a giant dish, and when you spoke into it, it reflected the sound back and made it louder. You could use it to speak in a whisper to someone 17 meters away.? Bill: It all sounds so cool. I wish I could have gone with you? Judy: I know, but we can go together this weekend. I'd love to go there again!? Bill: That sounds like a great idea!
新人教版高中英语选修2Unit 2 Bridging Cultures-Discovering useful structures教学设计
The grammar of this unit is designed to review noun clauses. Sentences that use nouns in a sentence are called noun clauses. Nominal clauses can act as subject, object, predicate, appositive and other components in compound sentences. According to the above-mentioned different grammatical functions, nominal clauses are divided into subject clause, object clause, predicate clause and appositive clause. In this unit, we will review the three kinds of nominal clauses. Appositive clauses are not required to be mastered in the optional compulsory stage, so they are not involved.1. Guide the students to judge the compound sentences and determine the composition of the clauses in the sentence.2. Instruct students to try to learn grammar by generalizing grammar rules, controlling written practice, and semi-open oral output.3. Inspire the students to systematize the function and usage of noun clause1.Instruct students to try to learn grammar by generalizing grammar rules, controlling written practice, and semi-open oral output.2.Inspire the students to systematize the function and usage of noun clauseStep1: The teacher ask studetns to find out more nominal clauses from the reading passage and udnerline the nominal clauses.
新人教版高中英语选修2Unit 3 Food and Culture-Discovering useful structures教学设计
The newspaper reported more than 100 people had been killed in the thunderstorm.报纸报道说有一百多人在暴风雨中丧生。(2)before、when、by the time、until、after、once等引导的时间状语从句的谓语是一般过去时，以及by、before后面接过去的时间时，主句动作发生在从句的动作或过去的时间之前且表示被动时，要用过去完成时的被动语态。By the time my brother was 10, he had been sent to Italy.我弟弟10岁前就已经被送到意大利了。Tons of rice had been produced by the end of last month. 到上月底已生产了好几吨大米。(3) It was the first/second/last ... time that ...句中that引导的定语从句中，主语与谓语构成被动关系时，要用过去完成时的被动语态。It was the first time that I had seen the night fact to face in one and a half years. 这是我一年半以来第一次亲眼目睹夜晚的景色。(4)在虚拟语气中，条件句表示与过去事实相反，且主语与谓语构成被动关系时，要用过去完成时的被动语态。If I had been instructed by him earlier, I would have finished the task.如果我早一点得到他的指示，我早就完成这项任务了。If I had hurried, I wouldn't have missed the train.如果我快点的话，我就不会误了火车。If you had been at the party, you would have met him. 如果你去了晚会，你就会见到他的。
新人教版高中英语选修2Unit 3 Food and Culture-Reading and thinking教学设计
The discourse explores the link between food and culture from a foreign’s perspective and it records some authentic Chinese food and illustrates the cultural meaning, gerography features and historic tradition that the food reflects. It is aimed to lead students to understand and think about the connection between food and culture. While teaching, the teacher should instruct students to find out the writing order and the writer’s experieces and feelings towards Chinese food and culture.1.Guide the students to read the text, sort out the information and dig out the topic.2.Understand the cultural connotation, regional characteristics and historical tradition of Chinese cuisine3.Understand and explore the relationship between food and people's personality4.Guide the students to use the cohesive words in the text5.Lead students to accurately grasp the real meaning of the information and improve the overall understanding ability by understanding the implied meaning behind the text.1. Enable the Ss to understand the structure and the writing style of the passage well.2. Lead the Ss to understand and think further about the connection between food and geography and local character traits.Step1: Prediction before reading. Before you read, look at the title, and the picture. What do you think this article is about?keys:It is about various culture and cuisine about a place or some countries.
新人教版高中英语选修2Unit 5 First Aid-Discovering useful structures教学设计
You have no excuse for not going.你没有理由不去。He was punished for not having finished his homework.他因未完成作业而受到惩罚。2．动词ing形式复合结构由物主代词或人称代词宾格、名词所有格或普通格加动词ing，即“sb./sb.'s＋doing”构成。动词ing形式的复合结构实际上是给动词ing形式加了一个逻辑主语。动词ing形式的复合结构有四种形式：①形容词性物主代词＋动词ing②名词所有格＋动词ing③代词宾格＋动词ing④名词＋动词ingHer coming to help encouraged all of us.她来帮忙鼓舞了我们所有人。The baby was made awake by the door suddenly shutting.这个婴儿被突然的关门声吵醒了。Can you imagine him/Jack cooking at home?你能想象他/杰克在家做饭的样子吗？无生命名词无论是作主语还是作宾语都不能用第②种形式。Tom's winning first prize last year impressed me a lot.汤姆去年得了一等奖使我印象深刻。Do you mind my/me/Jack's/Jack leaving now?你介意我/杰克现在离开吗？Excuse me for my not coming on time．很抱歉我没能按时来。His father's being ill made him worried.他父亲病了，他很担心。We are looking forward to the singer's/the singer to give us a concert.我们盼望着这位歌手来给我们举办一场演唱会。
人教版高中地理必修2如何看待农民工现象精品教案
尽管如此，农民工作为一个新的社会阶层，其独特的经济需求和政治诉求应该得到充分的尊重。虽然农民工的“根”还在农村，但是他们已经脱胎换骨，日益成长为一个迫切需要社会认可的新兴阶层。3.农民工处于何种生存境况？作为“廉价劳动力”，工资水平低，拖欠时有发生。作为“超时劳动力”，工作时间极长，超负荷从事繁重工作。作为“高危劳动力”，社会保障缺失，各种安全事故频繁。4.农民工问题有多么重要？农民工问题关系到农业增效、农民增收和农村繁荣。农民工问题关系到工业化、城镇化和“以工补农、以城促乡”。农民工问题关系到社会主义和谐社会建设。5.解决农民工问题应该做些什么？构建城乡一体化就业体系。健全农民工权益保障制度。强化农民工输出地和输入地培训。稳妥解决农民工户籍问题。改进对农民工的管理和服务。
人教版高中地理必修3第五章第二节产业转移教案
1．阅读图5．16，说明产业向国外转移对日本经济的不利影响。点拨：图5．16直观的显示了产业转移对日本经济的不利影响：形成“产业转移出去的多，转移进来的少→国内生产投资不足，生产困难→市场萎缩→产业向外转移，外资不愿进入”的恶性循环。2．尽管重化工业的环境污染比较严重，但是却能为工业化的发展提供坚实的基础，因此成为发达工业的象征。日本、韩国的经济发展都经历了由轻工业(劳动密集型)到重化工业(资源密集型和资金密集型)到高科技工业(技术密集型)的阶段。(1）为什么日本、韩国在重点发展重化工业之前，要先发展劳动密集型工业?点拨：重化工业的发展一方面需要有一定的工业基础和技术工人，另一方面需要投入大量的资金，先发展劳动密集型工业有利于利用劳动力资源丰富且廉价的优势，积累资金和造就产业工人。所以，劳动力丰富的发展中国家或地区的工业化往往从优先发展劳动密集型工业开始。
人教版高中地理选修1第二章第二节月球和地月系教案
我们将三球仪中的月球放在地球和太阳之间时，对照“月相成因图”，它的暗面完全对着地球，而被太阳照亮的一面正对着太阳，我们看不到月亮，这时正是农历初一，被称为“新月”。又称为“朔”。 过了新月，月亮被照亮的部分慢慢地转向地球。当它从太阳的光辉中出现时，便出现了一丝蛾眉的弯月，此时为农历的初三、初四，因其形似蛾眉，被称为“蛾眉月”。此后，被太阳光照亮的部分越来越多地转向地球，当有一半亮面和一半暗面都对着地球时，明亮部分和黑暗部分的界线似乎像一张弓中没有拉动的弦。此时是夏历初七、初八，称为“上弦月”。这时月亮很明亮，有时在白天也能看见。在往后，月亮明亮部分越来越增大，当它转到与新月正好相反时，被太阳照亮的部分全都对着地球，看起来月亮就似一轮圆月，此时正是 农历十五、十六、十七，称为“满月”，又称为“望”。
人教版高中地理选修1第二章第一节太阳和太阳系教案
教学过程【导入新课】在太阳系中，九大行星就好像一个家庭中的九个兄弟，有许多共性，今天，我们就一起来了解九大行星在运动特征和结构特征上的共同之处。【板书】3．九大行星的运动特征和结构特征【启发引导】请同学们一起阅读地图册上的“太阳系模式图”，读图分析：（1）九大行星在公转的方向、轨道等方面有什么共性？（2）图中符号“i”、“e”代表什么意思？这两组数字能说明什么问题？九大行星公转的方向相同，均为自西向东转，我们称为同向性。符号“i”表示轨道倾角。（简介黄道、黄道面、轨道倾角）各大 行星的轨道倾角都很小，只有水星和冥王星的大一些，最大也不过17°，说明九大行星的公转轨道近似在同一个平面上，我们称之为共面性。符号“e”代表公转轨道椭圆的偏心率，即焦点到椭圆中心的距离与椭圆半长轴之比，它决定椭圆的形状。偏心率越小，越趋向于圆，当偏心率为0时，轨道就是圆。
人教版高中地理选修1第二章第三节月相和潮汐教案
创设情境、激发兴趣（5分钟）教师：（锁住屏幕）月相变化与我们人类关系十 分密切。美国著名总统林肯在年轻时担任律师期间曾利用月相变化规律，为当事人进行了成功的辩护，赢得了人们的尊重。月相变化是怎样变化的？月相变化有什么规律，这就是我们今天学习内容。（边演示 学习软件边介绍）我们今天学习主要有三个任务，其中学习任务一要注意在空格中填写农历日期，不认识有关月相的请参照下面的相关学习软件。 完成学习任务二时要注意运用学习软件，首先点击月相，观察日地与月地连线的关系，再观察月亮出没时间现太阳的关系。如满月时，日地与月地连线成1800夹角，当太阳从东方升起时，月亮从西方落下（6时）；当太阳从西方落下时，月亮从东方升起 （18时）。满月可见时间是18时到第二天6时。学习任务三请你先判 断图中月相是否正确，如果不正确，请把你认为正确的月相拖到图中适当位置。下面请你们开始学习。
人教版高中地理选修1第一章第一节天体和天体系统教案
【概括】天体是在不断的运动着的。运动着的天体互相吸引和互相绕转，从而形成天体系统。【板书】四、天体系统【启发】天体系统有大有小，大的天体系统又可包含许多小的天体系统。刚才同学们提到的三个天体系统之间是如何包含的呢？（银河系含太阳系，太阳系含地月系）【挂图讲解】地月系只有两个天体，地球和月球，它们之间的平均距离为384401千米；太阳系则包括太阳、九大行星、数十颗卫星及其它天体，整个太阳系的直径至少100亿千米以上；而银河系则拥有2000多亿颗太阳恒星及恒星系统，包括了我 们用肉眼能看到的所有恒星，其主体部分的直径达7万光年，太阳就处于距银河系中心2.3万光年的位置上。【讲解】银河系已如此庞大，是否 就是最大的天体系统呢？是否就是我们的宇宙呢？还远远不是。利用天文望远镜，我们可以观测到在银河系之外，还有约10亿个类似的天体系统，它们被统称为河外星系。