【课件】Unit 5 Using Language 2 课件-2021-2022学年高中英语人教版（2019）选择性必修第一册.pptx

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1、人教（人教（2020）选择性必修一）选择性必修一 Unit 5To understand the differences between chemical and organic farming and their advantages and disadvantages;To learn about the structure and language features of the text;To write an essay to express your views on chemical farming or organic farming by giving supporting

2、details.Sustainable Agriculturesociety(humans)environmenteconomy(profit)population:9.8 billion by 2050Pre-reading:predictionWhat is the text about?chemical farming and organic farmingWhat does the picture show?Where?What?Why?Read the text,check your prediction and answer the questions:What is chemic

3、al farming?What is organic farming?commonChemical farming is farming using chemical pesticides and artificial fertilizers.P3:Organic farming is simply farming without using any chemicals.What is organic farming?1.Chemical pesticides and artificial fertilizers have been in widespread use in farming s

4、ince the middle of the 20th century.When they were first introduced,many farmers welcomed them as a great way to fight crop disease and increase production.Over time,however,what some scientists have found is that their long-term use can sometimes harm both the land and peoples health.Paragraph 1-2F

5、ind out the main idea and supporting details.2.For example,pesticides can damage but also helpful ones.In addition,these chemicals for a long time.This affects the crops and,in turn,the animals and humans who digest them.In fact,some pesticides like DDT As for chemical fertilizers,corps grown with t

6、hem usually grow too fast to be rich.but inside and they often have less flavor as well.main idea D The problems with chemical farmingsupporting details3supporting details1supporting details2As an alternative,some farmers have switched to organic farming,and many customers have turned to organic foo

7、d when they shop at the local grocery.Organic farming is simply farming without using any chemicals.For example,many organic farmers use natural waste from animals as fertilizer.This makes the soil in their fields richer in minerals.It also keeps the air,soil,water and crops free of chemicals.Paragr

8、aph 3 A What organic farming ismain ideasupporting details1Paragraph 4Organic farmers also use many other methods to produce rich soil.They often change the kind of crop grown in each field every year.For instance,they may grow corn or wheat Organic farmers also plant diverse crops that use differen

9、t depths of soil to help keep it rich.For example,peanuts main idea C Organic methods for producing rich soilsupporting details1supporting details2Paragraph 5Some people would prefer to stop the use of man-made chemicals in.What keeps them from doing so is the fact that chemical farming serves the h

10、igh demand for food around the world.Organic farming is nowhere near able to meet that need.Therefore,there is still a long way to find a suitable solution that puts sufficient food on the dinner table while keeping people and the environment as healthy as possible.supporting details1 B Why man-made

11、 chemicals are still used in farmingbacteria and insectsprohibiteddamage they usegrow too fastnutritionnatural waste from animalsevery yeardifferent depthsdemand for food around the worldchange the kind of cropDACB1 Why did many farmers welcome the introduction of chemical farming?Many farmers welco

12、med them as a great way to fight crop diseases and increase production.2 What concerns many people about the use of pesticides?Their long-term use can sometimes harm both the land and peoples health.3 What is one problem with the use of chemical fertilisers?Crops grown with them usually grow too fas

13、t to be rich in nutrition.ReadanswerReadanswer4 How is organic farming different from chemical farming?Organic farming is simply farming without using any chemicals.Organic farmers focus on keeping their soil rich and free of diseases through natural means.5 Why do organic farmers change the kind of

14、 crop grown in a field every year?Different crops are grown because they put important minerals back into the ground,making it ready for the next batch of crops.6.What is the goal of using organic farming methods?Do you think it can be reached?Why or why not?Post-readingTo grow good food while avoid

15、ing damage to the environment or to peoples health.Read the text again and complete the table below with the help of the signpostsFarmingBenefit problemsolutionChemical farmingOrganic farmingfight crop diseasesincrease production (serve the high demand for food around the world)1.pesticidesometimes

16、harm land and peoples healthkill helpful bacteria and insectsstay for a long time and affect crops,animals and people 2.chemical fertilizernot rich in nutrition and have less flavorswitch to organic farming keep soil rich and free from disease through natural meansnatural waste from animals as ferti

17、lizerchange the kind of crop in each field every yearplant diverse crops using different depths of soilunable to serve the high demand for food around the world There is still a long way to find a suitable solution.Chemical pesticides and artificial fertilizers have been in widespread use in farming

18、 since the middle of the 20th century.When they were first introduced,many farmers welcomed them as a great way to fight crop disease and increase production.Over time,however,what some scientists have found is that their long-term use can sometimes harm both the land and peoples health.Paragraph 1F

19、ind out the signposts语篇标识词语篇标识词contraststress the problemsParagraph 2For example,pesticides can damage but also helpful ones.In addition,these chemicals for a long time.This affects the crops and,in turn,the animals and humans who digest them.In fact,some pesticides like DDT As for chemical fertiliz

20、ers,They may look beautiful on the outside,but inside and they often have less flavor as well.Add more information and emphasizingexplain points by giving examplesin turn:to show points in a particular orderas for:introduce new informationAs an alternative,some farmers have switched to organic farmi

21、ng,and many customers have turned to organic food when they shop at the local grocery.For example,many organic farmers use natural waste from animals as fertilizer.This makes the soil in their fields richer in minerals.It also keeps the air,soil,water and crops free of chemicals.Paragraph 3something

22、 offering the possibility of different choices可供选择的事物可供选择的事物 introduce new informationshow more detailsParagraph 4Organic farmers also use many other methods to produce rich soil.They often change the kind of crop grown in each field every year.For instance,they may grow corn or wheat Organic farmer

23、s also plant diverse crops that use different depths of soil to help keep it rich.For example,peanuts Paragraph 5Some people What keeps them from doing so is the fact that chemical farming serves the high demand for food around the world.Organic farming is nowhere near able to meet that need.Therefo

24、re,there is still a long way to find a suitable solution that puts sufficient food on the dinner table while keeping people and the environment as healthy as possible.to draw a conclusionTransitions between ideas语篇逻辑上的过渡和转换语篇逻辑上的过渡和转换SignpostsWords to show transitionsFunctionbut also;and as well;In

25、addition,;also;MoreoverAdd more information and emphasizingFor example;For instanceExplain or support a pointTherefore,Hence State a conclusionbut;however,nevertheless contrastIn turnSequencingAs for;As an alternativeIntroducing a new topic/thingpersonallyGive your own opinion通过聚焦体现文本逻辑的连接词，掌握更为丰富的语

26、言表达，迁移运通过聚焦体现文本逻辑的连接词，掌握更为丰富的语言表达，迁移运用到之后的议论文写作中，增加表达的逻辑性和说服力。用到之后的议论文写作中，增加表达的逻辑性和说服力。1.Is the author of the passage for or against organic farming?How do you know?Some people would prefer to stop the use of man-made chemicals in agriculture entirely.Organic farming is nowhere near able to meet tha

27、t need.Therefore,there is still a long way to find a suitable solution that puts sufficient food on the dinner table while keeping people and the environment as healthy as possible.Discussion2.What other disadvantages of organic farming can you think of?higher cost of producing foodgreater effort re

28、quired to farming 3.What is the text type?You need to state your own standpoint in an argumentative essay议论文议论文 on chemical or organic farming.如何写表达如何写表达观观点的文章点的文章发表议论就是通过议论或说理来表达作者的见解和主张，作者对某一问题持有一种看法，为了使读者同意自己的看法，提出若干理由，试图说服别人。发表议论时，我们要注意三个要素：论点、论据、论证。Write an argumentative essay giving your opini

29、on on chemical or organic farming.Is the author of the passage for or against organic farming?How do you know?What other disadvantages of chemical farming did the author not list?How might the following items be problems and how important are they for organic farming?What other disadvantages of orga

30、nic farming can you think of?Step 1 Discuss these questions in groups.Step 2 Decide whether your group supports chemical farming or organic farming.Topic sentence:In my opinion,_farming is preferable to _ farming because _ Point 1:_ （Detail）_Point 2:_ （Detail）_Point 3:_ （Detail）_Conclusion:_ Step 3

31、Use your outline to write a short essay giving your opinion on the topic.Sample WritingIn my opinion,organic farming is preferable to chemical farming because of the benefts to the environment as to people,and because organic food is more nutritious.To begin with,chemical farming harms the environme

32、nt.Since chemical pesticides are not found in nature,normal natural processes cannot get rid of them.Instead,the chemicals tend to accumulate in the soil and water,and are absorbed in the food chain,where they poison wildlife and domestic animals.This affects us directly,because we end up eating pla

33、nts,dairy products,eggs,and meat that have high levels of pesticides.Think about it:The purpose of the pesticides is to kill“pests”,that is,to kill insects.Something that can kill an insect probably is not healthy for a person to eat.While it may be true that the food we eat does not have enough pes

34、ticide in it to kill us immediately,over the years this pesticide may cause us health problems or give us diseases such as cancer.Finally,organic food is generally more nutritious than food grown with man-made chemicals.If you remember a few years ago,there was the case of watermelons literally expl

35、oding in the fields because they had been given chemicals to make them grow faster.The reason why they exploded was that they contained too much water,because the farmers had used too many chemicals and the weather was unusually wet.As it turns out,such chemicals are commonly used in farming to grow

36、 larger crops more quickly.Do you really want to eat watered-down fruit and vegetables which have been rushed to market?They cannot possibly taste as good as organic vegetables,nor can they be as nutritious.In closing,I would like to suggest buying organic food.Yes,the price is a little higher,but the small price we pay extra will bring us huge rewards in the end.