Unit4 Space Explorations单元整体教学设计-高中英语新教材必修第三册大单元整体

Unit 4 Space Exploration 子主题1：走近宇航员Period 1 Listening and SpeakingWorksheetUnit 4 Listening and SpeakingActivity 1: Watch and answer➢What does this video mainly talk about?➢Can you name any of the requirements according to the video?Activity 2: Talk about the questions in groups➢Do you know any other things about the selection procedure for astronauts?➢Can you name any famous astronauts from China or abroad?Activity 3: Look and predictLook at the picture and the title, and then try to predict what will be talked about in the listening part.Activity 4: Listen for gistListen for the first time and get the main idea of the conversation.➢Who are the speakers?➢What are the speakers talking about?➢Why do they have the conversation?Activity 5: Listen and tick (教材38页活动2)Listen for the second time and tick the correct statement(s).Activity 6: Listen and fill (教材38页活动3)Listen for the third time and fill in the blanks with the correct NUMBERS.Activity 7: Listen and make a list (教材39页活动4)Activity 8: Discuss in pairs➢Do you want to be an astronaut in the future? Why?➢If you are determined to become an astronaut, what might be the hardest part you need to overcome?Activity 9: Make a speechSuppose you are an astronaut from CNSA, and you are invented to a school to make a speech about the requirements for becoming an astronaut.Homework1. Write a short essay about the requirements for becoming an astronaut;2. Search the Internet for information about an astronaut that you admire and get more information about how he/she became an astronaut. Share the information with your classmates in the next lesson.。

教学设计to the rest of the class.Presentation (1)Presentation (2)Presentation (3)Listen to the news report and fill in the table.Shenzhou 16 Manned Spaceship Launch time May 30,2023Launch site Jiuquan Satellite Launch Center Launch vehicle Long March2F carrier rocketTaikonauts Jing Haipeng, Zhu Yangzhu, Gui Haichao 设计说明：学生通过课前搜集信息，绘制思维导图，准备相关图片及成果新闻报道等方式将重要的太空任务、事件及相关成就进行全方位展示，从而进一步内化项目主题，锻炼他们整合运用语言的能力，同时也培养学生自主学习及合作学习的能力。

Step6 DiscussionWhat is the secret of China's success on aerospace?(Space spirit :intelligence,selfreliance,perseverance,cooperation and dedication)设计说明：本环节以讨论形式进行，组织学生讨论中国太空探索取得成功的原因，培养学生动脑、动手、动口的能力以及团队合作意识。

同时，鼓励学生学习太空科学家和宇航员们不畏艰险、勇于探索的精神。

Step7 ExtensionIntroduce the origin and significance of Space Day Of China to students to deepen their understanding of space exploration.设计说明：本环节向学生介绍中国航天日的设立目的及意义，在总结知识的同时又升华了德育目标：传承航天精神，为国家科技事业的发展贡献自己的智慧和力量。

Unit 4 Space ExplorationReading and Thinking【教学目标】1. Read quickly to get detailed information according the timeline; read carefully to summarize the main idea.2. Learn the reading skills—finding the timeline and summarizing the main idea by finding the words or ideas.3. Have a passion for our country and be proud of the space exploration.4. Learn to think critically about the space exploration.【教学重难点】1. Read quickly to get detailed information according the timeline; read carefully to summarize the main idea.2. Learn the reading skills—finding the timeline and summarizing the main idea by finding the words or ideas.【教学过程】Step 1 Lead in—Small talkWatch a video about Space experiment and discuss what you have learnt from it.Step 2 Before reading—Predict the contentSpace: the final frontierChinese meaning: 太空：最后的边境Frontier: the border, which might mean the human’s recognition edge or exploration edge.From the title and the pictures and the title, we can know that the article might be about the development of space exploration. It broadens us human’s recognition edge or explorationedge. So it is an exposition.Step 3 While reading—Task 11. Read the text. Several sentences have been removed from it. Choose the correct sentences A —D to fill each gap in the text.A. Although scientists try to make sure nothing goes wrong, accidents can still happen.B. They also really wish to discover other planets that are suitable enough to support life.C. The future of space exploration remains bright.D. After many experiments, they succeeded in making rockets that could escape Earth’s gravity.Answers: BDAC2. Scan the text and match the main idea.Para 1A ．China has made great progress in exploring space. Para 2B ．The future of space exploration remains bright. Para 3C ．The achievements that the USSR and America made. Para 4D ．People have always wanted to explore space. Para 5E ．The desire of people to explore the universe never died. Answers: DCEAB3. The main idea of the passage is the space exploration of humankind.Step 4 While reading—Task 2Read the text and fill in the tabletimeevents On 4 October 1957 The Sputnik 1 satellite was unched by the USSR andsuccessfully 2.orbited around Earth.On 12 April 1961 Yuri Gagarin became the first person in the world 3.to go(go) into space.On 20 July 4.1969Armstrong stepped onto the moon ，saying ，“That's one smallSummarize the main idea When the main idea is not clearly stated in a topic sentence, you should read the full paragraph or passage carefully and find the words or ideas that repeat themselves. They are likely evidence of the author’s main idea.Step 5 While reading—Task 3Read the text again and answer the following questions. Then have Ss share their answers.Q1: Who was the first person in the world to go into the space?Q2: Who was the first man to orbit Earth in Shenzhou 5 spacecraft?Q3: In which satellites all the astronauts died during their missions?Q4: What is the function of the International exploration?Q5: What can you learn from Para 4?Q6: What is the attitude to the space exploration?Step 6 Post reading1. RetellHave some Ss try to retell the text.2. Critical thinkingQ1: What do you think of the space exploration?I think it is beneficial to us. Through further study of space, people will make full use of it in the future, such as the space experiments by Wang Yaping in Tian Gong 1.Q2: If you are determined to be an astronaut, what should you prepare at present?First of all, I should study hard to get a related college degree. Besides, I must keep mental and physical healthy.Step 7. HomeworkTry to summarize the structure of the article by a mind map.。

Unit 4 Space ExplorationPeriod 1 Listening and Speaking & Pronunciation教材分析开篇页主题图展现的是2019年1月3日“玉兔二号”与嫦娥四号着陆分离后驶抵月球表面的画面。

嫦娥四号首次实现在月球背面着陆，是中国航天事业发展的一座里程碑。

这一图片不仅能够增强学生的民族自豪感，还能激发学生讨论的热情。

听说板块的主题是“讨论如何成为一名宇航员”（Talk about how to become an astronaut）。

这一板块从学生感兴趣的话题切入单元主题，主要是为了充分激发学生的好奇心和求知欲。

让学生了解中国宇航员的选拔条件及过程，既能开阔学生的眼界，了解我国航天事业发展的需求，又能从宇航员的经历描述中体会到一个道理：天赋固然重要，但任何辉煌的成就都离不开勤奋的学习、刻苦的磨练和不懈的努力。

教学目标1. 能正确理解使用下列词汇：astronaut, rocket, universe, gravity, satellite。

2. 了解并掌握英语重读规则，分辨连贯的句子中哪些词需要重读，哪些词不需要重读。

3. 通过阅读开篇页信息，熟悉单元主题语境，预测单元内容，明确学习内容。

4. 能在听的过程中有效获取关键信息，尤其是与数字相关的信息。

5. 学习太空科学家和宇航员们不畏艰险、勇于探索的精神。

教学重难点【教学重点】引导学生在听的过程中准确获取与数字相关的信息。

【教学难点】引导学生运用所学语言和文化信息进行自主表述。

教学过程Task 1Step 1 Warming-up1. Think of the questions below.When you see “Space Exploration”, what do you think of?What do you expect to learn about space exploration?What do you know about the development of China’s space exploration?设计意图：通过提问启发学生开展“头脑风暴”，激活学生的背景知识。

Unit 4 Space ExplorationPeriod 1 Listening &Speaking＆Talking教学设计The themes of this part are “Talk about how to become an astronaut” and “Talk about life in space”.As Neil Armstrong said “Mystery creates wonder and wonder is the basis of man’s desire to understand. Space is difficult for human to reach, therefore, humans are full of wonders about it. However, if wanting to achieve the dream of reaching the Moon, some of our human should work hard to be an astronaut at first. Part A(Talk about how to become an astronaut) is a radio interview in a radio studio, where the host asked the Chinese astronauts about his story how to become an astronaut. Yang Liwei told his dreamed to be an astronaut since childhood. Then he worked hard to get into college at 22. The next 10 years, he gradually became an experienced pilot. At the same time, to be an astronaut, he had to study hard English, science and astronomy and trained hard to keep in good physical and mental health and to practise using space equipment. Part B (Talk about life in space) is also an interview with the astronaut Brown, who is back on the earth. The host Max asked about his space life, such as his emotion about going back the earth, the eating, shower, brushing, hobbies and his work. Part A and Part B are interviews. So expressing curiosity about the guests’ past life is a communicative skill, which students should be guided to learn.1. Students can get detailed information about how Yang Liwei became an astronaut and Max’s space life.2. Students learn to proper listening strategy to get detailed information---listening for numbers and taking notes.3. Students can learn related sentences or phrases to express their curiosity like “ I wish to know...” “I’d love to know...”4. Students can learn more about the space and astronauts, even be interested in working hard to be an astronaut1. Students can get detailed information about how Yang Liwei became an astronaut and Max’s space life.2. Students learn to proper listening strategy to get detailed information---listening for numbers and taking notes.3. Students can learn related sentences or phrases to express their curiosity like “ I wish to know...” “I’d love to know...”Part A Listening and Speaking--- Talk about how to become an astronautStep 1 Lead in--Small talkLook at the picture on Page 38 and tell your classmates what you can see.I can see the solar system and the Chinese astronaut Yang Liwei waving to us.Step 2 Before-listening1. As for the space exploration, what do you think about ?Space explorationAnswers: space, shuttle, astronaut, spaceship, rocket, space suit, solar system, ...2.Can you name any famous astronauts from China or abroad ?China: Yang Liwei, Wang Yaping, Zhang Xiaoguang,...Abroad: Neil Armstrong, Gagarin,...3.Do you know anything about the selection procedure for astronauts ? make a list of the possiblerequirements.Get good education; flying experience; excellent health; rich knowledge; special training,...Step 3 While-listening---Task 1Listen to the interview and tick the correct statements.☑ 1. The audience is curious about how Yang Liwei became the first Chinese astronaut.☐ 2. Mr Yang always believed that he would become an astronaut one day.☑ 3. Mr Yang was selected to attend pilot training with 13 other people.☐ 4. To become an astronaut in China, you have to have 1,350 hours of flying experience.☑ 5. Astronauts not only had to learn how to use space equipment, but also had to do a lot of mentaland physical training.Step 4 While-listening---Task 2Listen again and fill in the blanks with the correct numbers.1. Yang Liwei graduated from college at the age of 22.2.Before he joined China’s space programme, Mr Yang trained as a fighter pilot for 10 years.3.Mr Yang was one of the 14 pilots who were chosen to train for space flights.4.At the time when Mr Yang entered the space programmes, astronauts had to shorter than 172 cm inheight and less than 70 kg in weight.5.Mr Yang became China’s first astronaut when he was 38 years old.Step 5 While-listening---Task 3Listen to the interview again and make a list of the requirements for becoming an astronaut.●Education background: college degree●Experience: rich experience of fighter●Health condition: perfect physical and mental health and body shape; proper height and weight●Courses: English, science and astronomy●Special training: using space equipment; physical and mental trainingStep 6 Post-listening---SpeakingWork in pairs. Discuss whether you would like to be an astronaut in the future and give your reasons. Use what you have learnt from the interview to help you.A: You know, I think being an astronaut would be cool.B：Do you want to work in space in the future ?A: I’m not sure, but I think it might be too difficult for me. There are so many requirements. First of all, you must be intelligent enough to get a related college degree. Then you have to work hard to be a great fighter pilot for rich experience. In addition, you have to keep in a perfect physical and mental health and learn science and astronomy well.B: So what might be the most difficult part for you.A: I guess it might be the astronomy, which is too difficult for me.Part B Listening and Talking ---Talk about life in spaceStep 1 Before -listeningLook at the pictures below and guess whether they would be useful for astronaut in space.soaptowel guitar showerMicrowave pen tape tissue Answers: soap, towel, guitar, pen, microwave, tissueStep 2 While -listeningMax is interviewing Captain Brown about his life in space. Listen to the interview and answer the questions.1. What did Captain Brown usually wear inside the station ?shorts and T -shirt.2. How did he prepare his food in space ?He didn’t prepared his food. Because they didn’t have cooking in space. They chose what they wanted to eat before going to space and then the food was prepared and stored for them. They just needed to heat the food and enjoyed it.3. How did he keep himself clean in space ?He used a soapy towel to wash and swallowed their tooth paste after brushing his teeth.4. How did he spend most of his time in space ?doing different experiments.5.What did he do during his free time ?played the guitar.6.What did he look forward to most during his stay in space ?his weekly video call with his family.Step 3 TalkingWork in groups. Imagine you are going to a space camp and Captain Brown has been invited to give a talk. Discus the questions you would like to ask him and then make a list.ExampleA: Hey, guys. We’re going to meet a real astronaut. Isn’t it exciting ?B: Yeah. I can’t wait to see Captain Brown! I’m really curious about his life in space. I have plenty of questions to ask him.C: Such as ?B: Oh, such as what facilities do they have in space to support their daily life ?C: That sounds like a good question. But I’d like to know about how astronauts sleep. What do they do so as to not to float around while they sleep ?Expressing curiosity●I’d love to know... ●I wonder how/what/why/...●Well, I’d really like to find out...●I’d particularly like to know...●I’m most curious about...●I’m most interested to discover...●I’m very keen to know...●I wish to know...●I hope you won’t mind me asking about...Unit 4 Space ExplorationPeriod 2 Reading and ThinkingSpace: the final frontier教学设计The theme of this unit focuses on “space exploration.”Students will learn about the training and experience needed to become an astronaut. The text is mainly about the development of space exploration. On the one hand, the text helps students to have a good understanding about the great feats humans haveachieved, on the other hand, they will further understand the contributions that we Chinese have achieved, and feel confident and proud about our homeland and strengthen their love for our country. The teacher should instruct students to aim high and study harder to make great progress in the space career if possible.1.Read about the development and value of space exploration.2.Explore the mysteries of the universe and the achievements in space exploration.3.Skillfully use the vocabulary of this text to cultivate self-study ability4.Develop cooperative learning ability through discussion.1. Enable the Ss to talk about the development and value of space exploration.2. Guide the Ss to summarize the main idea of each paragraph as well as the main idea of the text.3. Help Ss comprehend the main reasons for space exploration.Multi-media, textbook, notebooks.Step 1: Warming up and predictionLook at the title and the pictures of the text and predict what the text will be about?2.What are the main reasons for space exploration?Step2: Fast reading tasksRead the passage quickly and choose the correct sentence to fill each gap in the text.A. Although scientists try to make sure nothing goes wrong, accidents can still happen.B. They also really wish to discover other planets that are suitable enough to support life.C. The future of space exploration remains bright.D .After many experiments, they succeeded in making rockets that could escape Earth's gravity.Step3: scan for details.Read it again and find out the details.Which satellite was launched by the USSR in 1957?2. Who was the first person in the world to go into space?3. Who was the first man to orbit Earth in Shenzhou 5 spacecraft?4. In which satellites, all the astronauts died during their missions?5. What’s the attitude to the space exploration according to the author?Step4 : Read for main ideasRead quickly and figure out the main idea of each paragraph.Paragraph 1Paragraph 2Paragraph 3Paragraph 4Paragraph 5Step 5: Critical thinking:1.What do you think of the space exploration?2. If you are determined to be an astronaut, what should you prepare at present?3. Do you think space is the final frontier? And why?Step 6: consolidation.People have always wanted to learn more about space. Before the mid-20th century, most people felt (1)_________ (travel) into space was an impossible dream. However, (2)____ the help of scientists, people succeeded in realizing their dream (3) _________(explore) space. On 4 October 1957, the Sputnik 1 satellite (4) ____________(launch) by the USSR.(5) ________________ scientists try to make sure nothing goes wrong, accidents can still happen. These disasters made everyone (6)____________(disappoint), but people still believe in the importance of (7) ________(carry) on space exploration. In 2003,China became the third country to (8)____________(independent) send humans into space. Then Shenzhou 6 and 7 completed (9)__ second manned orbit and the first Chinese spacewalk. In spite of the difficulties, scientists hope future (10)__________ (discovery) will not only enable us to understand the universe but also help us survive well into the future.Step 7：learning strategies1.迅速浏览文章, 抓住关键词, 理清论点和论据2.找出段落中支持topic sentence的detailed words, 从而总结出段落大意。

Unit 4 SPACE EXPLORATIONReading and ThinkingLearning objectivesAt the end of this class, I will be able to:1. summarize the main idea for each paragraph based on topic sentences.2. use some reading strategies 阅读策略.3. have a better understanding of the title, and the spirits of space exploration.“Space, the final frontier. These are the voyages of starship Enterprise (进取号星舰), its continuing mission: to explore strange new worlds, to seek out new life forms and civilsations, to boldly go where no man has gone before.”Circle some clues that may help!Mission tips:When filling the gaps, we should pay attention to:The linking word(s): now, however, although, after, ...Pronoun(s): they, it, this, ...Repeated word(s) the same or similar words or phrasesThe position of the missing sentenceA. Although scientists try to make sure nothing goes wrong, accidents can still happen.B. They also really wish to discover other planets that are suitable enough to support life.C. The future of space exploration remains bright.D. After many experiments, they succeeded in making rockets that could escape Earth’s gravity.Whilereading: structurePara 1 “Are we alone? What’s out there?” Looking up at the stars, people have always wanted to learn more about space, and scientists work hard to find answers. They make vehicles to carry brave people into space to find out the secrets of the universe._______________________________________________________________________A. Although scientists try to make sure nothing goes wrong, accidents can still happen.B. They also really wish to discover other planets that are suitable enough to support life.C. The future of space exploration remains bright.D. After many experiments, they succeeded in making rockets that could escape Earth’s gravity.Whilereading: structurePara 2 Before the mid20th century, most people felt travelling into space was an impossible dream. However, some scientists were determined to help humans realise their dream to explore space. _________________________________________________________________________________ On 4 October 1957, ... and on 12 April 1961, ... Over eight years later, on 20 July 1969, ...Para 3 _________________________________________________________________________ All the astronauts on the USSR’s Soyuz 11 and America’s Challenger died during their missions. These disasters made everyone sad and disappointed, but the desire to explore the universe never died. This is because people believe in the importance of carrying on space exploration despite huge risks. ...Whilereading: plete the time chart: Para.4Besides the spirits, what else contributes to China’s rapid progress in space exploration? spirits of the manned space programpolitical supportfinancial supportdevotion of scientistsdevelopment of hightechnologyProfessor Li:We are ready to go. Join me in China’s space exploration.How many stars do you get?I have grasped the basic words of space exploration.I have successfully finished a gapfilling by analysing the sentences and using some reading skills.I have summarized the structure and the main idea.I have found some details to understand the achievements of space exploration.I have taken an active part in finishing all the missions.Assignment你的外国朋友Frank想要了解中国的航天成就，请你给他写一封信，内容包括：1. 写信目的；2. 具体成就；3. 取得成就的原因。

新世纪版英语高三年级第二学期-Unit4SpaceExploration-教案设计Unit 4 Space Exploration【教学目标】1．分清定语从句各个关系代词和关系副词的用法，熟练运动定语从句进行描述和会话。

2．学会依照空间顺序进行写作，描述一个地方。

3．能运用一些词语和句型描绘航天知识和自己的感受。

【教学重难点】1．关键词：语言知识类fiercely, sufficient, anxiety, mark, pour…into…,enormous, be determined to do…, leave…behind, it wasn’t long b efore…, put pressure on…, set out, get over, land on, boost, signal, emergence, mission, in spite of, s portion of…,compare…with…,infinity, conce ntrate on…, rewarding, benefit from…专业术语类long-range, carrier rocket, atomic weapons, satellite, capsule, orbit, superpower, space shuttle, space station, manned, blast off, solar system, communications satellite, medical engineering, …2．功能：（1）Advertising for space travel （描述“天文”）Where reality exceeds your dreams…This will be an once-in-a-lifetime opportunity.Before the flight, the attendees will take a 6-day training programmer, during which they learn all about the vehicle and space flight.The flight to an altitude of 100 kilometers will be breathtaking, the experience of a lifetime!The entire ride will last between 30 to 90 minutes, depending on the vehicle chosen.Passenger safety is the prime requirement for our company. All possible measures are taken to provide the lowest-risk ride possible.（2）Describing things using relative clauses （“定语从句”描述事物）The rocket that made flight into space possible were indeed a spectacular achievement.3．语法点：定语从句的复习【教学过程】1．Reading作为“宇宙”这一主题的引入，教师可以利用“头脑风暴”的教学手段，结合小组合作的方式，让学生列出尽可能多的关于“宇宙”的词汇（可根据词性分类）。

第一部分 单元整体教学设计PEP Book 3 Unit 4 Space ExplorationPeriod 8 Extensive reading 教学设计. 单元整体教学 设计理念. 单元主题意义 探究 . 单元学习目标和课时安排教学设计大纲使用教材：人教版（2019）必修第三册单元名称：Unit 4 Space Exploration 课例名称：Homes on Mars (Extensive reading)实施年级：高一年级第二部分 本课时教学设计. 教材分析. 教学目标与重难点 . 教学过程 . 作业设计 . 板书设计第一部分单元整体教学设计单元整体教学设计理念本单元的教学设计是基于王蔷教授的双重视域英语学科大观念，对教材单元进行重组和优化，搭建起完整的教学单元。

在践行教学评一体化教学设计理念，以及指向学科核心素养发展的过程中，尊重学生的认识发展水平，推动知识的结构化，结构的功能化，能力的素养化，力求在情景化的活动中，给予学生沉浸式的体验，推动学生的深度学习。

在促进语言学习和意义探究的过程中，培养解决问题的能力，最终达成学科育人的目标。

单元主题意义探究主题名称：人与自然——宇宙探索——地球与宇宙奥秘探索主题意义下的单元大观念：了解太空知识，学习航天精神，增强民族自豪感单元及课时主题概述：本单元围绕“太空探索”这一主题展开，内容涉及人类探索太空的历史与成就（重点了解我国航天事业的发展和成就）、宇航员的选拔、太空中的生活、火星探索计划、天文百科知识，以及关于“人类耗费时间和金钱去探索太空是否值得”这一话题的讨论。

让学生关注人类太空探索的进程，不仅是为了开阔学生视野，增长见识，积累相关的语言，更重要的是让学生感受和体会科学家以及宇航员们为航空航天事业的发展不断努力、勇于开拓的精神。

宣扬这种精神，也是为了激励青少年勤奋学习、刻苦钻研、不畏挫折，努力探索自己的发展道路，立下远大志向，为国家科技事业的发展奉献自己的智慧和力量。

人教版高中英语第三册Unit 4 SPACEEXPLORATION教学设计文本简析本单元阅读材料探讨的主题是：太空探索。

该主题涵盖了太空探索的发展历程及其探索意义。

其目的在于促进学生多维度深入了解“太空探索”这一前沿科学研究行为，引导学生理性看待“太空探索”对人类发展的深远意义，从而树立学生正确的科学观。

本文是一篇说明文。

该文本结构清晰，文章由5个段落构成，每个段落主题独立。

文本首段始于两个问题，点明了人类进行宇宙探索的初衷，其一是探究宇宙的秘密，这是基于知识认知层面的回应；其二是寻找新的资源，这是基于人类生存层面的考量。

第二段从国际视角出发，概述了在探索太空早期所取得的标志性成就；第三段简述了太空探索遭遇的危险及例证科学家坚定探索的决心；第四段聚焦中国在“探空”方面所取得的成果；第五段展望未来，呼应首段，再次点明太空探索的意义及目的。

在进行教学设计时，要帮助学生厘清文本的主要内容和内在结构；通过段落内容的解读填补缺失信息句，提炼段落主题大意。

在填补缺失信息句方面，教师可以从“一找位置，二寻词汇，三看逻辑”三个层面开展策略指导；在概括段落大意上，如何寻找主题句；在主题句缺失的情况下，如何概写主题句等方面进行方法引导。

在教师的引导下，学生延伸思考太空探索的危险和挑战及人类对太空探索可能带来的好处，最终达到内化语言、提升思维品质，培养文化品格的学习目的。

第一课时一、教学内容填补缺失信息句，提炼段落主题大意，思考太空探索的挑战和意义。

二、课时目标1. 理解文本标题含义，预测文本内容。

2. 通过阅读和分析，了解文本文体，辨识段落的主题句，分析关键句和关键信息，提炼段落的主题大意，熟悉和掌握基本的阅读策略。

3. 通过深入挖掘和探讨，思考人类面临的挑战和太空探索的意义。

三、教学过程Activity 1：Activating the background knowledge related to space本活动旨在为落实课时目标1作铺垫。