Ex3

1-c

2 - e

3-b

4-a

5-d

Ex4

1. If we pollute the air, we will have breathing problems.

2. If humans pollute the water, a lot of the creatures.

3. If we cut trees in the forest, there will be more floods.

4. If the soil is contaminated, the plants will die.

5. If there is noise pollution, humans and animals can lose their hearing.

Ex5

1. If you walk to school, you will make the air less polluted.

2. If you use recycled paper, you will save a lot of trees.

3. If the Earth got hotter, everything would die soon.

4. If parents teach their children about the three R's, they will help a lot for the environment.

5. If you want to save a lot of electricity, use solar energy.

Bài 3

1 C

2 E

3 B

4 A

5 D

Bài 4

1 If we pollute the air,we will have breathing problems

2 If people pollute the water, a lot of fish will die

3 If we cut down trees in the forest, there will be more floods

4 If the soil is polluted, plants will die

5 Is there is noise pollution, people and animals will have hearing problems

Bài 5

1 you will help reduce air pollution.

2 you will save trees.

3  the sea level will rise.

4 children will help the environment.

5  you will have to turn off all the lights before going out.

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