C. It can kill harmful pests.

D. It can make the soil richer in mineral.

（2）What is the advantage of using chemical fertilizers?

A. Leaving chemicals in the ground for a long time is good for water supply.

B. They can get the soil exhausted.

C. They can kill helpful bacteria.

D. They can kill harmful pest.

5．What does the word"it" (Line 3,Para4 ) probably refer to？（no more than 2 words）

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6．Skim the passage again and find the main idea.

can cause many problems, so is becoming more popular.

Step 3 Discussing

If you want to plant some crops, what kind of fertilizer will you use? Why?

(Grown in clean air; free of pollution; rich in nutrition; do good to people's health and the environment; food tastes better )

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Step 4 Presenting

Present the results of the discussion and answers to the questions.

Step 5 Teacher's evaluation

Step 6 Testing

1. Fill the blanks with proper words.

In recent years, scientists have discovered that using 1

fertilizers for a long time can 2 the land and also people's health. There are several problems 3 by chemical fertilizers. They hurt the health of the land, 4

in the water for a long time and 5 people's bodies

6 their food. 7 farming is becoming more popular 8 some farmers and many customers after these discoveries came out. Organic farming does not use any 9 . There are many organic farming methods 10

making the land healthy and productive. All of these methods try to produce good food and to keep the environment and people healthy.

2. Translation.

1.然而，最近科学家发现长期使用这些肥料会造成土地受损，甚至更危险的是，会对人们的健康造成危害。

2.他们通常每隔几年换种农作物，比如在种玉米或小麦后的一年种豌豆或大豆。

3.像豌豆、大豆一类的农作物将重要的矿物质带回土壤，使之适宜于种植那些要求土壤肥