人教版高中英语必修四Unit2 Using Language Chemical or organic farming课件.pptx(课件中不含音视频素材)

1、Unit2 CHEMICAL OR ORGANIC FARMING?化化学耕作还是有机耕作？学耕作还是有机耕作？Over the past half century,using chemical fertilizers has become very common in farming.在过去的半个在过去的半个世纪里，在耕作中使用化肥已经非常普遍。世纪里，在耕作中使用化肥已经非常普遍。Many farmers welcomed them as a great way to stop crop disease and increase production.很多农民喜欢使用很多农民喜欢使用化肥。

2、把化肥作为防治农作物病虫害和提高产量的化肥。把化肥作为防治农作物病虫害和提高产量的重要手段。重要手段。Recently,however,scientists have been finding that long-term use of these fertilizers can cause damage to the land and,even more dangerous,to peoples health.然而，最近科学家发现长期使用然而，最近科学家发现长期使用这些肥料会造成土地受损，甚至更危险的是，会对这些肥料会造成土地受损，甚至更危险的是，会对人们的健康造成危害。人们的健康造成危害。

3、What are some of the problems caused by chemical fertilizers?化肥带来的问题有哪些呢？化肥带来的问题有哪些呢？First,they damage the land by killing the helpful bacteria and pests as well as the harmful ones.首先，化肥在杀死病菌和害虫的同时也会杀死有益首先，化肥在杀死病菌和害虫的同时也会杀死有益的细菌和昆虫，从而破坏土地。的细菌和昆虫，从而破坏土地。Chemicals also stay in the ground and undergro

4、und water for a long time.化学物质还会在地里和地下水中保存很化学物质还会在地里和地下水中保存很长时间，长时间，This affects crops and,therefore,animals and humans,since chemicals get inside the crops and cannot just be washed off.而这会影响到庄稼，进而影响到动物和人类，因为而这会影响到庄稼，进而影响到动物和人类，因为化学成分会进入到农作物中，并且不能被冲洗掉。化学成分会进入到农作物中，并且不能被冲洗掉。These chemicals in the fo

5、od supply build up in peoples bodies over time.随着时间的推移，随着时间的推移，食物中的这些化学成分会在人体中堆积。食物中的这些化学成分会在人体中堆积。Many of these chemicals can lead to cancer or other illnesses.很多化学成分能导致癌症或其他疾病。很多化学成分能导致癌症或其他疾病。In addition,fruit,vegetables and other food grown with chemical fertilizers usually grow too fast to be f

6、ull of much nutrition.另外，施过另外，施过化肥的水果、蔬菜和其他食物通常生长得过快而营化肥的水果、蔬菜和其他食物通常生长得过快而营养不足。养不足。They may look beautiful,but inside there is usually more water than vitamins and minerals.它们表面上很好看，但里面通常是含过它们表面上很好看，但里面通常是含过多的水分，而不是维生素和矿物质。多的水分，而不是维生素和矿物质。With these discoveries,some farmers and many customers are b

7、eginning to turn to organic farming.由于这些发现，由于这些发现，一些农民和消费者开始转向有机耕作。一些农民和消费者开始转向有机耕作。Organic farming is simply farming without using any chemicals.有机耕作就有机耕作就是不用任何化学肥料的耕作。是不用任何化学肥料的耕作。They focus on keeping their soil rich and free of disease.农民关心的是保持土壤肥沃并且免农民关心的是保持土壤肥沃并且免受病害。受病害。A healthy soil reduces

8、 disease and helps crops grow strong and healthy.健康的土壤会减少病虫害并且帮助农作物茁健康的土壤会减少病虫害并且帮助农作物茁壮成长。壮成长。Organic farmers,therefore,often prefer using natural waste from animals as fertilizer.因此，有机耕作因此，有机耕作的农民通常喜欢把天然的动物粪便当作的农民通常喜欢把天然的动物粪便当作肥料。肥料。They feel that this makes the soil in their fields richer in mine

9、rals and so more fertile.他们认为这样会使他们认为这样会使地里的土壤更富含矿物质，因而也会更地里的土壤更富含矿物质，因而也会更加肥沃，加肥沃，This also keeps the air,soil,water and crops free from chemicals.同时还可以让空气、土壤、水以及农作同时还可以让空气、土壤、水以及农作物不受化学物质的污染。物不受化学物质的污染。Organic farmers also use many other methods to keep the soil fertile.有机耕作的农民也使用很多其他有机耕作的农民也使用很多其

10、他的方法来保持土地肥沃。的方法来保持土地肥沃。They often change the kind of crop in each field every few years,for example,growing corn or wheat and then the next year peas or soybeans.在同一块地里，他们经常每隔几年就换在同一块地里，他们经常每隔几年就换种农作物。种农作物。例如，种玉米和小麦后来年再改种豌豆或例如，种玉米和小麦后来年再改种豌豆或大豆。大豆。Crops such as peas or soybeans put important mineral

11、s back into the soil,making it ready for crops such as wheat or corn that need rich and fertile soil.像豌豆或大豆这样的农作物将重像豌豆或大豆这样的农作物将重要的矿物质带回土壤，从而使之适宜于种植要求土地肥要的矿物质带回土壤，从而使之适宜于种植要求土地肥沃的农作物，比如玉米或小麦。沃的农作物，比如玉米或小麦。Organic farmers also plant crops to use different levels of soil,for example,planting peanuts t

12、hat use the grounds surface followed by vegetables that put down deep roots.有机耕作的农民还种植多有机耕作的农民还种植多种农作物来利用不同层次的土壤。比如，他们先种植种农作物来利用不同层次的土壤。比如，他们先种植生长于浅层土壤的花生，然后再种植生根于深层土壤生长于浅层土壤的花生，然后再种植生根于深层土壤的蔬菜。的蔬菜。Some organic farmers prefer planting grass between crops to prevent wind or water from carrying away t

13、he soil,and then leaving it in the ground to become a natural fertilizer for the next years crop还有一些有机耕作者喜欢在农作物之还有一些有机耕作者喜欢在农作物之间种草，以防止水土流失，并且把草留在地里，从而间种草，以防止水土流失，并且把草留在地里，从而成为来年农作物的天然肥料。成为来年农作物的天然肥料。These many different organic farming methods have the same goal:to grow good food and avoid damaging

14、 the environment or peoples health.这些不同的有机耕作这些不同的有机耕作的方法有着同样的目标：种植好的粮的方法有着同样的目标：种植好的粮食，避免损害环境或者人们的健康。食，避免损害环境或者人们的健康。What is the substance we put on the soil which makes crops grow?It is fertilizer.How many kinds of fertilizers do farmers use?There are two kinds.They are chemical fertilizers and nat

15、ural ones.Which kind do farmers use when they are doing organic farming?Do you know about organic farming?ORGANIC FARMING Organic farming is simply farming without using any chemicals.1.Why are chemical fertilizers so popular in farming today?I.Read the passage and answer the following questions.The

16、y are a great way to stop crop disease and increase production.2.What problems can be caused by using chemical fertilizers?They can damage the land by killing helpful bacteria and pests and by staying in the ground and underground water for a long time.They damage peoples health by building up in th

17、eir bodies and leading to cancer or other illnesses.3.What is organic farming?Organic farming means growing crops without using any chemicals.4.What is the main reason for using organic farming methods?The main reason for using organic farming methods is to grow good food and to avoid damaging the e

18、nvironment or peoples health.II.Read the text again and fill in the blanks.Chemical FarmingAdvantages Stopping crop disease and increase _productionChemical FarmingDisadvantagesDamaging the land:killing the helpful _ Damaging peoples health:Many chemicals in the food supply can lead to cancer or oth

19、er illnesses.Food grows too fast to be full of much _.bacteria and pestsnutritionOrganic farming_To grow good food and avoid damaging the environment or peoples healthGoalOrganic farmingMethods Using _ waste from animals as fertilizerChanging _ in each field every few years Using _ of soil to plant

20、crops Planting _ between cropsgrassnaturalthe kind of cropdifferent levelsIn what condition do you think green food grow?The advantages of green fooddirty air dirty water supplies in industrial areas many chemical fertilizersclean,fresh air clean water supplies away from industrial areas free of che

21、mical fertilizersMain idea of the passageChemical fertilizers can cause many problems,so organic farming is becoming more popular.ORGANIC FARMINGStructure of the textI using chemical fertilizers for a long time can hurt the land and also peoples healthII Problem caused by chemical fertilizers1.Damag

22、e the land by killing the helpful bacteria and pests as well as the harmful ones2.Lead to cancer or other illness.3.Food grown with chemical fertilizers look beautiful,but inside there is usually more water than vitamins and minerals.Organic farming is becoming more popular with some farmers and man

23、y customers after these discoveries came out.IV Other methods to keep the soil fertile.ProjectPersuade the farmers in our county to grow the crops by organic farming with the knowledge learnt.What is organic farming?What fertilizer should they use?Why?How to plant the different crops?Language points

24、1.lead to用法用法寓词于境寓词于境 阅读下列句子，注意阅读下列句子，注意lead to的意的意思和用法。思和用法。1.His carelessness led to the accident.2.This test is obviously bad because it leads to incorrect learning.3.Too much work and too little rest often leads to illness.自我归纳自我归纳 lead to意为意为“_”,后多跟名词或代词。后多跟名词或代词。导致、造成导致、造成(后果后果)联想联想 result in引

25、起引起(某种结果某种结果)、使获得、使获得(某种某种成果成果)、结果、结果。如：。如：The accident resulted in two deaths.result from由由造成、因造成、因而产生。如：而产生。如：Sickness sometimes results from eating too much.即学即练即学即练 用用lead to的适当形式完成句子。的适当形式完成句子。1.Students should always remember that hard work is the main way which _ success.2.The bad weather _ a

26、 terrible accident a few days ago.led toleads to2.focus用法用法 根据语境推断根据语境推断focus在下列句子中的在下列句子中的含义含义,并从并从a-d中找出与每句话中的中找出与每句话中的focus相符合的英文释义。相符合的英文释义。1.The focus of the meeting changed from population growth to the education of women.2.Bring the object into focus if you want a clear photograph.3.She tried

27、 to focus her mind on her work.4.She turned the camera and focused on Martins face.a.the thing,person,situation,etc.that people pay special attention tob.a point or distance at which the outline of an object is clearly seen by the eye or through a lensc.to point a camera at something,and change the

28、controls slightly so that you can see that thing clearly d.to give special attention to one particular person or thing,or to make people do thisfocus作名词作名词,意为意为“焦点、中心点焦点、中心点”;作动词作动词,意为意为“集中、聚焦集中、聚焦”,常构成短常构成短语语focus on,意为意为“集中集中(注意力、精力注意力、精力等等)于于”。翻译下列句子。翻译下列句子。1.Because of his strange clothes,he imm

29、ediately became the focus of attention when he entered the office.由于他的奇装异服由于他的奇装异服,所以一走进办所以一走进办公室他便成了大家注意的焦点。公室他便成了大家注意的焦点。2.Focus your camera on those trees.3.Im so tired that I cant focus on anything today.把照相机的焦点集中在那些树上。把照相机的焦点集中在那些树上。今天我太累了今天我太累了,精神集中不起来。精神集中不起来。3.keep free from “远离远离”或或“避避免免”ke

30、ep free from emotional reactions 避免激动的反应避免激动的反应 keep free from restrictions 避免受到限制避免受到限制4.Crops such as peas or soybeans put important minerals back into the soil,making it ready for crops such as wheat or corn that need rich and fertile soil.分析分析 本句结构比较复杂。其主干结构为本句结构比较复杂。其主干结构为:主句主句(Crops put import

31、ant minerals back into the soil)+状语状语(making it ready for crops)。状语中又包含状语中又包含“make+it+形容词形容词”结构和由结构和由that引导的定语从句引导的定语从句(that need rich and fertile soil)。5.Some organic farmers prefer planting grass between crops to prevent wind or water from carrying away the soil,and then leaving it in the ground t

32、o become a natural fertilizer for the next years crop.分析分析本句的主干结构是一个简单句本句的主干结构是一个简单句,其结其结构是构是:主语主语(farmers)+谓语谓语(prefer)+并列宾语并列宾语(planting.+leaving.)。其中其中between crops和和in the ground作作地点状语。地点状语。两个宾语后面又分别带有一个不定式两个宾语后面又分别带有一个不定式作目的状语（作目的状语（to prevent wind or water from carrying away the soil和和to becom

33、e a natural fertilizer for the next years crop）。）。What is the main topic of the conversation?The possible bad effects of chemical fertilizers on the fruit and vegetables that we eat today.1.Paul thinks that Carrie is not telling him the truth.2.Using chemical fertilizers always makes vegetables empty inside.3.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.T or F.T FT FT Collect some information about the safety and importance of green food.