人教版必修4Unit2 Using language Reading 课件

1、Unit 2 Using languageReadingChemical or organic farming?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v

2、t. 减少；减缩减少；减缩n. 根；根源根；根源Words preview skim underline summary 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

3、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 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 th

4、e advantages of GM foods? The world population has topped 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:First

5、 reading ( 3ms ) Read the passage on page14 , then find out the main idea of each paragraph.Para 1: Para 2:Para 3:Para 4: Long-term use of fertilizers can cause damage to the land and people s health.The problem caused by chemical fertilizers .Some farmers and many customers are beginning to turn to

6、 organic farming.Organic farmers also use many other methods to keep the soil fertile. Second reading ( 5ms )Read the text again and answer the following questions:1 Why are chemical fertilizers so popular in farming today?2 What problems can be caused by using chemical fertilizers ?3 What is organi

7、c farming ?4 What is the main reason for using organic farming methods ?1.Why are chemical fertilizers so popular in farming today ?They can stop crop disease and increase production.2 What problems can be caused by chemical fertilizers ?There are three problems. First, chemical fertilizers affect t

8、he soil and the water supply badly. Second, they allow farmers to grow the same crop year after year and exhaust the soil. Third, they kill both helpful and harmful pests. Organic farming is simply farming without using any chemicals .3 What is organic farming ?4 . What is the main reason for using

9、organic farming methods ?A healthy soil reduces disease and helps crops grow strong and healthy .Third reading ( 8ms )Read the text again, and fill in the following forms.Methods of organic farmingAdvantages of methods1 Farmers use natural waste from animals.1 This makes the soil richer in minerals

10、and so more fertile.2 Farmers 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 differe

11、nt levels of soil.4 Farmers 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.What is the disadvantage of using chemical fertilizers?1.Leaving chemicals in the ground for a long time is not good for t

12、he soil or the water supply.2.Farmer often grow the same crop year after.As a result, the soil gets exhausted.3.Chemical fertilizers kill both helpful and harmful bacteria and pests.Retelling ( 8ms )Retell the text according to the chart: Organic farmingI. Crops growing with natural fertilizers.II.

13、Farmers prefer natural waste from animals.Natural fertilizerChemical fertilizer1.makericher and more fertile2.reduceand help strong3.the fertilizers killand healthy4.keep freefrom chemicals1.leavingis not good2.growyear after yearIII. Farmers change crops every two or three years. to make sure what

14、is left 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 upcharacter. 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 to

15、o 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 free 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

16、：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 from: 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。 5Recently ,however , scientists have been finding

17、 that long-term use of these fertilizers can cause damage to the land and , even more dangerous , to peoples health然而最近,科学家们发现长期使用化肥会给土地造成损害,甚至更危险的是会给人类的健康造成损害.1 (1)however为副词, 意为”然而，可是 ”，表转折，可用于句首,句末,句中,如在句中,起前后都要加逗号.例如: He , however ,couldnt pay for the education that young Albert needed . 然而,他无法支

18、付小艾伯特的教育费用(2)however为连词,引导让步状语从句,相当于相当于no matter how ,修饰形容词或副词.例如:However hot it is , he will never take off his coat .=No matter how hot it is , he will never take off his coat . 无论多么热,他都不会把外套脱掉.However fast you run , you cant catch up with a car .=No matter how fast you run , you cant catch up wit

19、h a car . 无论你跑得多快,你也赶不上一辆小汽车.2. have been finding 是现在完成进行时,现在完成进行时的特点是强调”动作的连续性”,但有可能已经终止.例如:He is very tired , he has been working hard all day . 他很累,他整天都在努力工作.He has been writing a letter. 他一直在写信.6They often change the kind of crop in each field every few years ,他们通常每隔几年就改变一块田地里作物的种类,every 或 “ever

20、y other+时间”表示”每隔每”,表示时间或空间的间隔. 具体用法是 : “every+基数词基数词+复数复数名词”;”every +序数词序数词+ 单数名词单数名词”.例如:every year 每年every two years / every second year / every other year每两年(每隔一年)every three years / every third year /every other two years .每三年(每隔两年)every four years / every fourth year / every other three years 每

21、四年(每隔三年)7Why are chemical fertilizers so popular in farming today ?为什么花费在现在的耕作中如此受欢迎?popular 的用法:(1)popular 为形容词,意为”受喜爱的，受欢迎的，当红的”. 常用短语: be popular with sb 受某人欢迎. 例如:This is one of our most popular designs . 这是我们是受欢迎的设计之一.Skiing has become very popular recently . 滑雪运动最近盛行起来.Im not very popular with

22、 my parents at the moment . 眼下爸妈对我很不高兴.(2)popular 为形容词,意为”通俗的,大众化的”.例如:popular music / culture / fiction 流行音乐/文化/小说popular 为形容词,意为”(概念,信仰,意见)普遍的，大众的，流行的”. 例如:Contrary to popular belief, women cause fewer road accidents than men . 与普遍的看法相反,妇女交通肇事比男人少. avoid doing sth.避免做某事prefer doing sth.宁愿做某事宁愿做某事prevent from使使免受免受1. What made Jia Sixie become interested in improving Chinese farming? He saw how some farms produced good crops and healthy animals and others did not.Reading task on Page 52 ( 15ms)Read the passage on Page 52, then finish the exercises on Page 53.2. How d