必修4 unit2Extensive reading.ppt

课标人教实验版 高一 Module 4 Unit 2;Extensive reading; 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 natural ones. ; Which kind do farmers use when they are doing organic farming ? Do you know about organic farming ? ; ORGANIC FARMING Organic farms use no man-made chemicals to increase crops or control insects and disease. The study showed that organic fields produced fewer crops, on average, than other fields. However, the scientists say the organic methods improved the health of the soil and used half as much energy. ; ; ; ;1. What is organic farming? ;2. Why do organic farmers grow peas or soybeans after corn or wheat?;3. What is the advantage of using natural fertilizer? ;4. What is the disadvantage of using chemical fertilizers? ;Secondly, farmers often grow the same crop year after year. As a result, the soil gets exhausted. Thirdly, chemical fertilizers kill both helpful and harmful bacteria and pests.;5. What’s the main idea of paragraph 3? ;6. Why do farmers grow their crops in such ways? ;ORGANIC FARMING I Crops growing with natural fertilizers;Natural fertilizer;Ⅲ Farmers change crops every two or three years. ...what is left in the ground after harvesting becomes a natural fertilizer for the next year’s crop.;Language points;(2) =mean 指的是，就…而言 “Slow” doesn’t refer to the action here, but to the train. “slow”在此不指动作，而指火车。 (3)提到，谈到 He referred to his past experiences. 他谈到了他过去的经历。 (4)查阅，参考; refer to...as 将......称为 refer sb. to... 让某人参考或求助于...... 2. to mention sb/sth 提到、说到 In his speech, he didn’t refer to the problem at all. 在他的演说中丝毫未触及那个问题。 3. Firstly, leaving chemicals in the ground for a long ti