1、Unit 4Global warming本单元的中心话题是人类当今面临的环境问题，主要探讨了“全球变暖”和“节约能源”等方面的问题。由于人类过多使用不可再生能源，大气中二氧化碳的含量逐年增加，导致全球气温上升。通过学习本单元，让学生了解能源分为“不可再生能源”和“可再生能源”，帮助学生树立“节约能源、保护环境”的主人翁意识。本单元的主要教学内容如下表所示：类别课程标准要求掌握的内容话题Global warming，pollution and the importance of protecting the earth词汇tendv.趋向；易于；照顾catastrophen.大灾难；浩劫oppo
2、sev.反对；反抗；与(某人)较量floodn.洪水；水灾statev.陈述；说明consequencen.结果；后果；影响glancev.看一下；扫视n一瞥existencen.生存；存在quantityn.量；数量commitmentn.承诺；交托；信奉rangen.种类；范围pollutionn.污染；弄脏tendencyn. 趋向；趋势growthn.增长；生长circumstancen.环境；情况motorn.发动机opposedadj.反对的，对立的cann.容器；罐头steadyadj. 平稳的；持续的microwaven.微波炉；微波widespreadadj.分布广的；普遍的
3、educatorn.教育工作者；教育家averageadj.平均的contributionn.贡献consumev.消费；消耗；耗尽；吃完presentationn.显示；演出subscribev.同意；捐赠；订阅disagreementn.分歧；不一致advocatev.拥护；提倡；主张randomadj.胡乱的；任意的refreshv. 使恢复；使振作mildadj.温和的；温柔的；淡的graphn.图表；坐标图；曲线图outeradj.外部的phenomenonn.现象electricaladj.电的；与电有关的fueln.燃料casualadj.随便的；偶然的datan.资料；数据nu
4、clearadj.核的；核能的trendn.趋势；倾向perprep.每；每一come about 发生；造成keep on 继续subscribe to 同意；赞成；订购on the whole 大体上；基本上quantities of 大量的on behalf of 代表一方；作为的代言人go up 上升；增长；升起put up with 忍受；容忍result in 导致so long as 只要be opposed to 反对and so on 等等even if 即使greenhouse effect 温室效应句型1.it_is human activity that has cau
5、sed this global warming.(emphatic “it”)2.it is a rapid increase when_compared_to other natural changes.(ellipsis)3.There is no doubt that_the_earth_is_becoming_warmer.(the appositive clause)4.Without the “greenhouse effect”，the earth would_be about thirtythree degrees Celsius cooler than it is.(the
6、subjunctive mood)功能1.同意与不同意(Agreement and disagreement)Exactly.Youre right.I agree.Thats correct/true/right.Im afraid I disagree with you. Im afraid not. I dont think so.No way. I dont agree. I doubt.2责备与抱怨(Blame and complaint)Im sorry to bring this up，but.Im sorry to have to say this，but.They shoul
7、dnt have done it. They are to blame.Perhaps/Maybe they should/ought to. Why dont you do something about it？语法“it”的用法(the use of “it”)(2).it_is human activity that has caused this global warming.教学重点1.Get students to know about global warming and its effect；to realize what we can do about global warm
8、ing.2Have students learn some useful new words and expressions about global warming and let them learn effective ways to master them.3Enable students to grasp and use the expressions of agreement and disagreement，blame and complaint.4Let students learn the new grammar item：the use of “it”(2)5Develop
9、 students listening，speaking，reading and writing ability.教学难点1.Enable students to master the use of “it”(2)2Let students learn to write a short passage to tell others how to solve the problem of global warming.3Develop students integrative skills.课时安排Periods needed：6Period 1Warming Up，Prereading，Rea
10、ding and ComprehendingPeriod 2Language StudyPeriod 3Grammarthe Use of “It”(2)Period 4Listening and Speaking Period 5Reading and WritingPeriod 6Summing Up，Learning Tip and AssessmentPeriod 1Warming Up，Prereading，Reading and Comprehending教学内容分析This is the first teaching period of this unit.The central
11、 part of this period is the reading passage with the title of “The Earth Is Becoming WarmerBut Does It Matter？” talking about the global issue which has a great effect on human beings life.Warming Up gives six pictures to help students list the sources of energy they can think of in our daily life.T
12、hen they will be led to discuss which energy source is “renewable” and which is “nonrenewable”This part is designed to help the students to recall their background knowledge about energy and prepares students for the whole unit.Prereading provides a picture of a greenhouse and then tells us what a g
13、reenhouse is and what “greenhouse gases” are.The students will be led to discuss what they think greenhouse gases do，leading to the topic of the reading passage.Reading is a passage from an environmental magazine for young people.It puts forward the possible effect of increased carbon dioxide in the
14、 atmosphere and different points of view about it.It also analyzes the causes of the earths increased temperature.It poses questions and encourages students to think about the issues.There are two graphs in it that tell us the “temperature difference from longterm average,18602000” and “carbon dioxi
15、de content in the atmosphere,19571997”Characters in the passageDr Janice Foster，George Hambley and Charles Keeling are all real persons and their views reflect the views of some scientists today.Comprehending consists of three written or oral exercises for the students to do so as to help the studen
16、ts to get a better understanding of the text，that is to say，to help the teacher to check how much the students have understood the text.三维目标设计Knowledge and skills1To know the meanings of the following new words and phrases：consume(消费；消耗；耗尽)，come about(发生；造成)，random(胡乱的；任意的)，phenomenon(现象)，subscribe(
17、同意；捐赠；订阅；签署文件)，subscribe to(同意；赞成；订购)，fuel(燃料)，quantity(量；数量)，quantities of (大量的)，tend(趋向；易于；照顾)，go up(上升；增长；升起)，per(每；每一)，data(资料；数据)，result in(导致)，trend(趋势；倾向)，catastrophe(大灾难；浩劫)，flood(洪水；洪灾)，oppose(反对；反抗)，opposed(反对的；对立的)，be opposed to(反对)，consequence(结果；后果)，state(陈述；说明)，range(种类；范围)，even if(即使)
18、，keep on(继续)，glance(看一下；扫视)，steady(平稳的；持续的)，steadily(平稳地，持续地)2To learn about some facts and views about global warming.3To learn how the information is organized.4To develop the students reading ability by skimming and scanning the passage.5To develop the students speaking ability by talking about g
19、lobal warming.Process and methods1While doing Warming Up the teacher can lead in the topic of this unit by showing students some pictures or videos about sources of energy，making the students recall their own knowledge about energy.2During Prereading the teacher can go around the classroom and discu
20、ss the questions with several students.This discussion should be studentcentered and lead them to the topic of global warming.The teacher should also ask the students to look at the graphs in the reading passage and try to find out the general idea of the text.3While doing Reading and Comprehending，
21、the teacher may first ask the students to read the text quickly to get the general idea of each paragraph.After reading the passage，students are encouraged to answer some questions and discuss the text structure.4To consolidate the contents of the reading passage，the students should be required to r
22、etell the text in their own words at the end of the class.Emotion，attitude and value1To make students realize the harm of global warming and the importance of environmental protection.2To develop students sense of cooperative learning.教学重、难点1To enable the students to learn about global warming and t
23、o develop their reading ability.2To enable the students to talk about what we should do to prevent global warming.Step 1Warming up1Warming up by reading and talking：Read through the exercise with the class.Put students in groups of four to talk about what we use energy for，what are the sources of th
24、ese energy and whether the sources are renewable or nonrenewable.Suggested answer：The six photos are：windmills；a coal power station；an oil refinery；a nuclear power plant；solar panels；a hydroelectric dam.2Warming up by discussion：Draw a form on the blackboard as follows：Things that use energySources
25、of energyRenewable/nonrenewable Let the students have a discussion and collect suggestions from students and write them under the appropriate heading.Suggested answer：Things that use energySources of energyRenewable/nonrenewable lightsheating television cassette player video recorder computer fridge
26、 stove hairdryer .coalnonrenewableoil nonrenewablenatural gasnonrenewablewind power renewablesolar energy renewablenuclear energy nonrenewablehydroelectric power renewablebiomass energy renewablegeothermal energy renewabletidal energyrenewableStep 2Prereading1Show a picture of a greenhouse to studen
27、ts and ask them what a greenhouse is made of and what its purpose is.Suggested answer：Its made of glass and plants can grow in it when its cold outside.Ask the students how it works.Suggested answer：The glass traps the heat from the sun，making the air warm so that plants grow better.2Ask students wh
28、at they think “greenhouse gases” are and what they think greenhouse gases do.Look at the picture above and explain it to their partners.Suggested answer：Greenhouse gases perform the same function as the glass in a glasshouse：they trap the heat of the sun and keep the air surrounding the earth warm.T
29、his is called the greenhouse effect.)Step 3Reading and comprehending1Fast readingAsk students to read the passage quickly so as to get the key words and general idea of each paragraph and answer the following questions：(1)What is the main topic of the article?_(2)Who wrote the magazine article？What
30、is the name of the magazine?_(3)What are the names of the three scientists mentioned in the article？Do they agree with one another?_Suggested answers：(1)Global warming/the warming of the earth.(2)Sophie Armstrong，Earth Care.(3)Dr Janice Foster，Charles Keeling，George Hambley.They dont agree with each
31、 other.2Detailed reading(1)Read the passage carefully and judge whether the statements are true(T) or false(F)Janice Foster believes that global warming is caused by the burning fossil fuels.()Natural gas is a greenhouse gas.()Carbon dioxide is a byproduct of burning fossil fuels.()People accept Cha
32、rles Keelings data because he took accurate measurements.()Flooding could be one of the effects of future global warming.()George Hambley believes scientists are just guessing about the effects of global warming.()George Hambley is worried about the effects of carbon dioxide on plant growth.()It is
33、clear what the effects of global warming will be.()(Suggested answers：TFTTTTFF)3Structure analyzing Ask students to read the text carefully and try to find out how many parts they can divide the text into and find out the main idea of each part.PartMain ideaPart 1(Paragraph _)Part 2(Paragraphs _ to
34、_)Part 3(Paragraphs _ to _)Part 4(Paragraph _)Suggested answer：PartMain ideaPart 1(Paragraph 1)To introduce a debate over the issue of global warming.Part 2(Paragraphs 2 to 5)To illustrate how global warming comes about.Part 3(Paragraph 6)To list two different attitudes among scientists towards glob
35、al warming.Part 4(Paragraph 7)Its up to readers to think and decide whether people should do something about global warming or not.Step 4Language studyDealing with any language problem if any(words or sentences students might not understand)to help the students to have a better understanding of the
36、text.Step 5Listening，reading aloud and underlining Ask students to read the passage aloud to the tape and let them pay attention to the pronunciation of each word and the pauses within each sentence.Tell them to pick out all the useful expressions or collocations from the passage while reading and c
37、opy them to the notebook after class as homework.Collocations：come about，There is no doubt that.，subscribe to，due to，greenhouse effect，quantities of，tend to，be trapped in，go up，result in，on the one hand.on the other hand，be opposed to，build up，keep on.Step 6RetellingAsk students to talk about global
38、 warming in their own words.Give them some key words and expressions on the blackboard.Then let them try to retell the passage.Step 7Homework1Learn the useful new words and expressions in this part by heart.2Try to find some data about global warming on the Internet，and show your class in the next p
39、eriod and talk about them.Step 8Reflection after teaching_About Global Warming(关于全球变暖)Global warming is the increase in the average temperature of Earths nearsurface air and oceans since the mid20th century and its projected continuation.Global surface temperature increased 0.740.18(1.330.32)between
40、 the start and the end of the 20th century.The Intergovernmental Panel on Climate Change(IPCC)concludes that most of the observed temperature increase since the middle of the 20th century was very likely caused by increasing concentrations of greenhouse gases resulting from human activity such as fo
41、ssil fuel burning and deforestation.The IPCC also concludes that variations in natural phenomena such as solar radiation and volcanic eruptions had a small cooling effect after 1950.These basic conclusions have been endorsed by more than 40 scientific societies and academies of science，including all
42、 of the national academies of science of the major industrialized countries.Climate model projections summarized in the latest IPCC report indicate that the global surface temperature is likely to rise a further 1.1 to 6.4(2.0 to 11.5)during the 21st century.The uncertainty in this estimate arises f
43、rom the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions.Most studies focus on the period up to the year 2100.However，warming is expected to continue beyond 2100 even if emissions stop，because of the large
44、 heat capacity of the oceans and the long lifetime of carbon dioxide in the atmosphere.An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation，probably including expansion of subtropical deserts.Warming is expected to be strongest in th
45、e Arctic and would be associated with continuing retreat of glaciers，permafrost and sea ice.Other likely effects include changes in the frequency and intensity of extreme weather events，species extinctions，and changes in agricultural yields.Warming and related changes will vary from region to region
46、 around the globe，though the nature of these regional variations is uncertain.Political and public debate continues regarding global warming，and what actions(if any)to take in response.The available options are mitigation to reduce further emissions；adaptation to reduce the damage caused by warming；and，more speculatively，geoengineering(地球工程)to reverse global warming.Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions.
