人教版新课标英语必修四《unit 2 working the land》课件（共7套打包）

chemical production bacteria pest nutrition mineral 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 Words preview * discovery focus soil reduce root n. 发现；发觉 n. 焦点；中心点 vt. 集中；聚焦 n. 土壤 vt. 减少；减缩 n. 根；根源 Words preview * skim underline summary comment 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.& vt. 表达意见; 做出评论 Words preview * 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) Expressions preview * Organic Farming What 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 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: 1).pest resistance 2).disease resistance 3).cold tolerance 4).drought tolerance/salinity tolerance 5).nutrition What 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: What is the main idea of this passage? This passage tells us something about organic farming. It means growing crops without chemical fertilizers which damage the soil. The organic farmers keep the soilrich and healthy in several ways. 1 Why are chemical fertilizers so popular in farming today? 2 What problems can be caused by using chemical fertilizers? 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