1、Unit 2 Saving the EarthTopic 2 All these problems are very serious.SectionCThe main activity is 1a. 本课重点活动是 1a。. Teaching aims and demands 教学目标1. Learn some new words and phrases:on earth, period, millions of, take away, rise, level, refer to2. Learn some useful sentences:(1) When it rains or when t
2、he wind blows, the earth is taken away.(2) The heat from the sun cant escape so the temperature is rising.3. Learn to talk about the harm of pollution:(1) Forests have become deserts, so more and more sorts of animals and plants are disappearing.(2) As a result, many rivers and lakes are now dead. (
3、3) Too much harmful radiation from the sun passes through the hole and reaches the earth directly.(4) It causes the level of the oceans to rise and the climate of the earth to change.4. Develop the students sense of environmental protection. . Teaching aids 教具图片/小黑板. Five-finger Teaching Plan 五指教学方案
4、Step 1 Review 第一步 复习(时间:4 分钟)通过检查作业，引导学生开拓思维，提出保护环境和水资源的具体措施，复习不定代词和副词。为学习新词汇作准备。(检查作业，并找学生汇报结果，引导学生如何保护水资源。)T: How do you protect our environment and save water?S1: Everyone should plant more trees.S2: We should do everything we can to save water.S3: Everybody should know the importance of forests.
5、S4: Pass laws against water pollution.S5: Collect and reuse waste water.Step 2 Presentation 第二步 呈现(时间:18 分钟)教师通过日常对话，借助 1a 中的图片，创设情景，导入新课，呈现新的词汇。1. (教师由日常对话，引出本课话题，呈现部分新词汇。)T: Whats the weather like today?Ss: Its T: As we know, Beijing often has sandstorms in spring. What causes the bad weather?Ss:
6、Cutting down too many trees. (展示 1a 第二幅图画。)T: Yes. All over the world, people have cut down millions of trees. And trees become fewer. (板书并要求学生掌握。) millions ofT: Cutting down too many trees causes the bad weather. How can trees affect the weather?S1: They can keep water from running away. S2: They c
7、an stop S3: T: Yes. Trees can stop the wind and water from taking the earth away.(板书并要求学生掌握。)take away2. (继续探讨上述问题，引出新词汇。)T: Anything else?(如果没有学生回答，继续如下问题。)T: Whats the air like in the forest?Ss: Its fresh.T: Yes. Why?Ss: (允许学生用汉语回答。)树能吸收二氧化碳并释放氧气。T: Thats right. Trees can breathe in carbon dioxide
8、 and breathe out oxygen.(展示 1a 第五幅图。)Please look at the picture.(板书并要求学生理解。)carbon dioxide: CO2oxygen: O2T: Where does CO2 come from?S4: Animals breathing.S5: Burning oil. For example, cars and buses.T: Yes. They have polluted the air. Carbon dioxide in the air has increased a lot. This has formed a
9、 “blanket” around the earth.(板书并要求学生理解。)blanketT: The heat from the sun cant escape, so the temperature is rising.(板书并要求学生掌握 rise；理解 escape。) escaperiseT: This is called “the greenhouse effect”.(板书并要求学生理解。) the greenhouse effectT: What happens to the icebergs(冰川)?Ss: Some parts of them change into w
10、ater.T: So it causes the level of the oceans to rise.(板书并要求学生掌握。) levelT: (展示 1a 第 4 幅图。)Please look at this picture. Around the earth, theres a special kind of oxygen called “ozone”.(板书并要求学生理解。) ozone: O3T: But now air pollution is destroying it and that has made a very big hole in the ozone layer.
11、(板书并要求学生理解。) ozone layerT: Too much harmful radiation from the sun passes through the hole and reaches the earth.(板书并要求学生理解。) radiation3. (让学生快速阅读 1a，用所给的词组填空。完成 1a。)T: We humans have lived on earth for only 35 000 years, but during this period we have changed our planet a lot in many ways. Now read
12、 the passage and then choose a proper title for each paragraph from the phrases above the passage. (板书并要求学生掌握。)on earth, period(学生完成后与教师核对答案。)4. (教师出示小黑板上的问题，让学生再读一遍课文后回答。)(1) Have we changed our planet in many ways?(2) Have people done good to the earth?(3) Why are more and more sorts of animals an
13、d plants disappearing?(4) Are many rivers and lakes dead now?(5) Is ozone important to the earth? Why?(6) Has carbon dioxide in the air increased a lot?(让个别学生回答，完成小黑板上的问题。)Step 3 Consolidation 第三步 巩固(时间:8 分钟)让学生再次读 1a，完成 1b，巩固本课的语言点，培养学生的阅读能力。1. (让学生再次读课文，完成 1b。)T: Read the passage again. Finish 1b
14、alone. (板书并让学生猜测 Mars 和 refer to 的汉语意思。掌握 refer to；了解 Mars。) Marsrefer to(学生完成后，师生核对答案。)2. (让学生齐读课文，保证每一个学生参与其中。)T: Now please read the passage together.3. (教师让学生讨论并找出新的或不懂的语言点，培养学生的自主学习能力。教师解释学生仍有疑惑的知识点并板书。)4. (让学生两人一组讨论，完成下面的表格。)T: How many kinds of pollution are mentioned in the passage? How do t
15、hey affect our environment? According to 1a, finish the form on the blackboard. (板书)Kind of pollution EffectStep 4 Practice 第四步 练习(时间:10 分钟)使学生了解各种污染对地球环境的影响，培养他们的环保意识。1. (让学生分组讨论，看哪组最快说出 O3，CO 2和温室效应的含义及其对环境的影响，并以此写一篇短文，完成 2。)T: Please read the passage again, discuss the meanings of the following e
16、xpressions in 2 in groups of 4, and then write down how they affect the environment.(学生讨论后，与教师核对答案。)2. (根据给出的提示词写一篇小短文，可先口述。)T: Write a short passage with the key words given.(板书关键词。)(1)changein many ways(2)important, destroy, too much, harmful radiation, cause cancer(3)increase a lot, blanket, rise
17、, change(4)serious, do somethingStep 5 Project 第五步 综合探究活动(时间:5 分钟)让学生讨论各种危害地球的污染方式，并就有关污染写一篇短文，培养学生综合运用语言的能力，增强学生的环保意识。1. (到目前为止，污染危害地球的方式已基本介绍完毕，可以让学生做专题讨论，以锻炼他们组织语言的综合能力。在此过程中，鼓励学生大胆发挥，做最大程度的拓展性讨论。最后通过汇报，教师检验活动成果。)T: OK, until now, we have learned so many kinds of pollution. Now please work in gro
18、ups and discuss them. After a moment, Ill ask some students to report it. 2. Homework:Write an article about the pollution. 板书设计：All these problems are very serious. Section Cmillions of When it rains or when the wind blows, the earth is taken away.take away As a result, many rivers and lakes are now dead. refer to The heat from the sun cant escape so the temperature is rising.It causes the level of the oceans to rise and the climate of the earth to change.
