1.Organic farming means growing crops__________ fertilizers.

A.with chemical

B.without chemical

C.with

D.without

2.The fertilizer that organic farmers prefer is__________.

A.natural waste from animals

B.chemical fertilizers

C.water

D.pests

3.Using chemical fertilizers can cause the following problems except that__________.

A.they affect the soil and water supply badly

B.they exhaust the soil

C.they kill both helpful and harmful pests

D.they make the soil richer

4.When farmers use__________ they keep the air,soil and water as well as the food supply free from chemicals.

A.fertilizers

B.natural waste from animals

C.chemical fertilizers

D.chemicals

5.The main idea of the last paragraph is that organic farmers__________.

A.keep their soil rich and healthy in three ways

B.insist on changing crops every two or three years

C.plant seeds in different layers of the soil

D.plant grass between crops

答案：1.B　2.A　3.D　4.B　5.A