人教版必修4Unit2 Using language Reading 课件知识讲稿.ppt

Unit 2 Using languageReading;Words preview; discovery focus soil reduce root ; skim underline summary comment ; 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.Why are chemical fertilizers so popular in farming today ?;;Organic farming is simply farming without using any chemicals .;4 . What is the main reason for using organic farming methods ?;Third reading ( 8ms ) Read the text again, and fill in the following forms.;Methods of organic farming;Methods of organic farming;What is the disadvantage of using chemical fertilizers?;Retelling ( 8ms ) Retell the text according to the chart: Organic farming I. Crops growing with natural fertilizers. II. Farmers prefer natural waste from animals. ;Language points;2 Many of these chemicals can lead to cancer or other illnesses. lead to: 导致；造成 Too much work and too little rest often lead to illness. ?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。 ;3 They focus on keeping their soil rich and free of disease. focus on:集中(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。 Olympus: Focus on life.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…免受（影 响，伤害登）；使不含（有害物） keep from: ?阻止; 妨碍 I hope you will keep from doing anything rash.? 我希望你不要做出任何鲁莽的事情来。 ;5Recently ,however , scientists have been finding that long-term use of these fertilizers can cause damage to the land and , even more dangerous , to