新人教版必修四Unit2 Using language课件

1、Words preview chemical production bacteria pest nutrition mineral adj. 化学的；关于化学的化学的；关于化学的n. 生产；制造生产；制造n. 细菌细菌n. 害虫；害兽；害鸟害虫；害兽；害鸟n. 营养；滋养；食物营养；滋养；食物n. 矿物；矿石矿物；矿石 discovery focus soil reduce root n. 发现；发觉发现；发觉n. 焦点；中心点焦点；中心点vt. 集中；聚焦集中；聚焦n. 土壤土壤vt. 减少；减缩减少；减缩n. 根；根源根；根源Words preview skim underline sum

2、mary comment vt. 浏览；略读浏览；略读vt. 画底线标出；强调画底线标出；强调n. 总结；摘要；概要总结；摘要；概要n. 评论；议论评论；议论vi.& vt. 表达意见表达意见; 做出评论做出评论Words preview Expressions preview build up lead to focus on keep free from/of逐渐增强逐渐增强; 建立建立; 开发开发导致导致; 造成造成 (后果后果) 集中集中 (注意力，精力等注意力，精力等) 于于使使免受免受(影响，伤害等影响，伤害等)；使使不含不含(有害物有害物) Organic FarmingWhat

3、 are genetically-modified foods? The term GM foods or GMOs (genetically-modified organisms) is most commonly used to refer to crop plants created for human or animal consumption using the latest molecular biology techniques. What are some of the advantages of GM foods? The world population has toppe

4、d 6 billion people and is predicted to double in the next 50 years. Ensuring an adequate food supply for this booming population is going to be a major challenge in the years to come. GM foods promise to meet this need in a number of ways:1).pest resistance 2).disease resistance 3).cold tolerance 4)

5、.drought tolerance/salinity tolerance5).nutritionWhat are some of the criticisms against GM foods? Most concerns about GM foods fall into three categories: environmental hazards, human health risks, and economic concerns.Read and answer:Read and answer:What is the main idea of this passage?This pass

6、age tells us something aboutorganic farming. It means growing crops without chemical fertilizers which damagethe soil. The organic farmers keep thesoilrich and healthy in several ways. 1 Why are chemical fertilizers so popular in farming today? 2 What problems can be caused by using chemical fertili

7、zers?3 What is organic farming?4 What is the main reason for using organic farming methods? Read the passage and answer the following questions.1 Why are chemical fertilizers so popular in farming today? They are a great way to stop crop disease and increase production.2 What problems can be caused

8、by using chemical fertilizers?They can damage the land by killing helpful bacteria and pets and by staying in the ground and underground water for a long time, They damage peoples health by building up in their bodies and leading to cancer or other illnesses.3 What is organic farming?4 What is the m

9、ain reason for using organic farming methods? Organic farming means growing cropswithout using any chemicals.The main reason for using organic farming methods is to grow good food and to avoid damaging the environment or peoples health. Find and write down the methods and advantages in the passage.M

10、ethods of organic farmingAdvantages of methodsFarmers use natural waste from animals.This makes the soil richer in minerals and so more fertile.Methods of organic farmingAdvantages of methods1 Farmers use natural waste from animals.1 This makes the soil richer in minerals and so more fertile.2 Farme

11、rs often change the kind of crop in each field every few years.2 Changing the crops renews the minerals in the soil and helps it become rich and healthy.Methods of organic farmingAdvantages of methods3 Farmers plant crops with different lengths of roots.3 This uses different levels of soil.4 Farmers

12、 sometimes plant grass between crops and leave it in the ground.4 This prevents wind or water from carrying away soil and acts as a natural fertilizer.Language points1 These chemicals in the food supply build up in peoples bodies over time.build up 增强增强; 建立；开发建立；开发 Hard working conditions build upch

13、aracter. 艰苦的工作条件能磨练人的性格。艰苦的工作条件能磨练人的性格。 2 Many of these chemicals can lead to cancer or other illnesses.lead to: 导致；造成导致；造成Too much work and too little restoften lead to illness. 过量的工作和过少的休息会引起疾病。过量的工作和过少的休息会引起疾病。All roads lead to Rome. 条条大道通罗马。条条大道通罗马。3 They focus on keeping their soil rich and fre

14、e of disease.focus on:集中集中(注意力，精力等）于注意力，精力等）于You should focus your attention on your work.把注意力集中在你的工作上。把注意力集中在你的工作上。 Olympus: Focus on life.奥林巴斯：瞄准生活。奥林巴斯：瞄准生活。 4 This also keeps the air, soil, water and crops free from chemicals. keeps free from /of: 使使免受（影免受（影响，伤害登）；使不含（有害物）响，伤害登）；使不含（有害物）keep fro

15、m: 阻止阻止; 妨碍妨碍 I hope you will keep from doinganything rash. 我希望你不要做出任何鲁莽的事情来。我希望你不要做出任何鲁莽的事情来。 Listening chemical fertilizer cow dung用化学肥料和有机肥料的区别用化学肥料和有机肥料的区别:The possible bad effects of chemical fertilizers on the fruit and vegetablesthat we eat today.As you listen to this dialogue, keep in mind w

16、hat you have just read about chemical fertilizers. What is the main topic of the conversation?Listen to the dialogue a second time. Decide if the following statements are true or false, according to the conversation.Give your reasons.1 Paul thinks that Carrie is not telling him the truth.2 Using che

17、mical fertilizers always makes vegetables empty inside.TrueFalse3 Todays fruit is not as healthy for people as fruit fifty years ago.4 Eating more vegetables might not always be good for us.5 All of todays vegetables look healthy but in fact are not.FalseTrueTrueListening text WHATS WRONG WITH THEVE

18、GETABLES?Girl: Hey, Paul, listen to this a magazine article about a farmer who used too much chemical fertilizer on his fields. When his vegetables were picked, they were all found to be empty!BOY: Empty? Youre joking, Carrie that cant be true!Girl: I didnt believe it either! This article says this

19、can happen sometimes with vegetables like cucumbers, carrots and pumpkins. This chemical fertilizer makes the vegetables grow fast to look big and beautiful, but theyre empty inside! BOY: You know, Ive noticed that sometimes my mum buys carrots from the supermarket that have big holes down the cente

20、r. I guess that must be from using chemical fertilizers! GIRL: Yeah, thats what the magazine says! The main point of the article, though, isnt about holes in our vegetables. Its talking about why the fruit and vegetables we eat today arent as nutritious as the ones our grandparents ate.BOY: What? My m