1. Farmers use natural waste from animals.

　　2. The soil is not exhausted.

　　3. They use the soil to best advantage. 　　1. This makes the soil richer in minerals and so

　　 more fertile.

　　2. Peas and soybeans renew the minerals in the

　　 Soil becomes rich and healthy.

　　3. They plant crops that need surface soil and next crops that grow at a deeper level. So the wind and water does not carry away the soil. All the richness of the soil is used. 　　For Exercise 3, here is a simple:

　　Organic farming means crops growing with natural fertilizers instead of chemical ones. Yhe natural fertilizer which is natural waste from animals does good to soil. It makes the soil richer in minerals while chemical fertilizers damage the soil, leaving chemicals fertilizers in the ground for a long time and killing both helpful and harmful bacteria and pests. Organic farmers keep the soil rich and healthy by changing plants every two or three years, planting different crops in different layers and planting grass between crops to prevent wind or water from carrying away the soil.

　　Step 4 Learn the Language points

　　Show the following sentences on the screen:

　　1. reduce v. make sth smaller in size, number, degree, price, etc

　　e.g. This company tries to increase profits by reducing costs.

　　2. We have reduced expenses this year.

　　3. supply v. give sb. sth. that is needed or useful

　　e.g. He kept me well supplied with cups of coffee while I wrote the report.

　　The shop was unable to supply what she wanted.

　　In Britain milk is supplied to each house in bottles.

　　4. whatever pron. any or every(thing)

　　e.g. we will be grateful for whatever amount you cab afford.

　　Whatever I have is yours.

　　5.refer to v. mention or speak of sb. / sth.

　　e.g. When I said some people are stupid, I wasn't referring to you.

　　Don't refer to this matter again.

　　6. year after year

　　e.g. The villagers plant trees on the hill year after year 　　Step 5 Discussion group work:

　　Divide the class into groups of four，and each of them has to do one of the following discussion.

　　Show students the questions:

1.What is the advantage of using natural fertilizer?