A Listen and circle
录音文字稿：
1. They help keep the air clean. They give us wood. What are they?
2. It makes the classroom dirty and messy. We should put it in the bin. What is it?
3. Most of our energy comes from them. There are not much of them on Earth.
4. People use it to make bags and bottles. Too much of it is bad for the Earth.
5. It is very useful. People drink it and use it to clean things.
6. It comes from cars. It makes the air dirty.
参考答案：
1. a 2. b 3. b 4. b 5. a 6. b
B Listen, write and match
录音文字稿：
1. We use water to wash clothes.
2. We use plastic to make bags.
3. We use wood to make tables and chairs.
4. We use waste bottles to make toys.
5. We draw pictures on paper.
6. We need oil to drive cars.
参考答案：
1. water, clothes, e 2. plastic, make, d 3. wood, tables, chairs, a
4. bottles, toys, c 5. pictures, paper, f 6. oil, drive, b
C Look and say
参考答案：略
D Read, judge and write
参考答案：
2. should, shouldn’t 3. shouldn’t, should 4. shouldn’t, should
5. should, shouldn’t 6. shouldn’t, should 7. should, shouldn’t
E Read and order
参考答案：
1. There is not much water in many places.
2. What makes the bedroom messy?
3. I can reuse paper to make a box.
4. He should not smoke in the bookshop.
5. Trees help keep the air clean.
F Read and judge
参考答案：
1．L 2. L 3. J 4. L 5. J 6. L
