人教版高一英语必修四Unit2Using language

Unit 2 Working the land Using language,chemical production bacteria pest nutrition mineral discovery,adj. 化学的; 关于化学的 n. 生产; 制造 n. 细菌 n. 害虫; 害兽; 害鸟 n. 营养; 滋养; 食物 n. 矿物; 矿石 n. 发现; 发觉,focus soil reduce root skim underline summary comment,n. 焦点; 中心点 vt. 集中; 聚焦 n. 土壤 vt. 减少; 减缩 n. 根; 根源 vt. 浏览; 略读 vt. 画底线标出; 强调 n. 总结; 摘要; 概要 n. 评论; 议论 vi. 做出评论,build up lead to focus on keep free from/of,逐渐增强; 建立; 开发 导致; 造成 (后果) 集中 (注意力, 精力等) 于 使免受(影响, 伤害等)； 使不含(有害物),It is fertilizer.,What is the substance we put on the soil to make crops grow?,How many kinds of fertilizers do farmers use? There are two kinds. They are chemical fertilizers and natural ones.,Organic Farming,chemical fertilizer,cow dung,用化学肥料和有机肥料的区别:,Reading,CHEMICAL OR ORGANIC FARMING?,Chemical fertilizers can cause many problems, so organic farming is becoming more popular. Organic farming means growing crops with natural fertilizer. The organic farmers keep the soil rich and healthy.,The main idea of the text:,Fast Reading,Long-term use of chemical fertilizers can cause damage to the land and peoples health.,Problems caused by chemical fertilizers.,The main idea of each paragraph,P1.,P2.,Farmers and customers turn to organic farming.,Other methods to keep the soil fertile.,P3.,P4.,Chemical fertilizer,Not good for the soil or the water supply,The soil gets exhausted.,Kill both helpful and harmful bacteria and pests,Careful Reading,Chemical farming,stop crop disease increase production,damage the land,by killing,affect crops,by staying,lead to cancer /illnesses,by building up,have less nutrition,by growing too fast,Organic farming,Natural waste from animals,Make the soil richer in minerals and more fertile,A healthy soil,Reduce diseases in crops,Help crops grow strong and healthy,Organic farming,use natural waste,make the soil rich in minerals,change the crop,put minerals back into soil, making,plant crops with different roots,use different levels of land,plant grass between crops,preventfrom, a natural fertilizer,Other methods: Change crops every two or three years,Corn, wheat,Peas, soybeans,Put the minerals back into the soil, making it rich and healthy,Crops that use the surface of the soil (peanuts),Crops that need a deeper level of soil (root vegetable),Make sure that what is left in the ground after harvesting becomes a natural fertilizer for the next years crop,1. Which statement is WRONG according to the text? A. All crops are organic. B. Recently, the term “organic farming” has gained another meaning. C. All farmers use fertilizers. D. Scientists believe some chemical fertilizers are better for people.,Choose the best answer.,D,2. Which is not the reason why organic farmers prefer natural waste from animals? A. It can keep the food free from chemicals. B. It can keep the air, soil and water free from chemicals. C. It can kill harmful pests. D. It can make the soil richer in mineral.,C,3. What is the advantage of using chemical fertilizers? A. Leaving chemicals in the ground for a long time is good for water supply. B. They can get the soil exhausted. C. They can kill helpful bacteria. D. They can kill harmful pest.,D,4. The organic farmers do the followings except _. A. adding fertilizers which is rich in mineral B. changing crops every two or three years C. planting seeds in different layers of the soil D. planting grass between crops to prevent the soil from being blown away,A,1. What is “organic farming”?,Answer the questions.,It refers to crops growing with natural rather than chemical fertilizers.,2. What do organic farmers prefer to use as fertilizer?,The fertilizer that organic farmers prefer is natural waste from animals.,Farmers grow peas or soybeans after corn or wheat so that peas and beans can put minerals back into the soil, making it rich and healthy and ready to grow more wheat or corn.,3. Why do organic farmers grow peas or soybeans after corn or wheat?,4. What is the advantage of using natural fertilizer?,Make the soil richer in minerals and so more fertile. Reduce diseases in crops and help them grow strong and healthy. Besides, keep the air, soil and water as well as the food supply free from chemical.,They are a great way to stop crop disease and increase production.,5. Why are chemical fertilizers so popular in farming today?,6. What problems are caused by using chemical fertilizers?,There are three problems. First, chemical fertilizers affect the 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.,7. 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 environment or peoples health.,Fill in the chart.,Farmers often change the kind of crop in each field every few years.,Changing the crops renews the minerals in the soil and helps it become rich and healthy.,This uses dif