Ex4:

1. polluted

2. environmental

3. poisonous

4. awareness

5. creature

6. chemical

7. speech

8. quality

Ex5:

1. litter

2. contaminated

3. makes

4. environmental

5. floating

6. from

7. fewer

8. pay

9. noisy

10. to

11. have

12. dramatic

13. action

14. population

15. about

Ex6:

1. E

2. C

3. A

4. D

5. B

Ex7:

1. People will have clean water if we use them carefully.

2. A lot of factories continue to dump toxic waste into lakes and rivers.

3. Remember to turn off the light when you do not use it.

4. Noise is any sound that is loud and constant.

5. How about plant more trees on the streets?

Ex8:

1. If Huong tidies the house, her mum won't feel angry.

2. The more polluted air makes people get more diseases.

3. A lot of underwater creatures die due to polluted water.

4. We need to use water carefully.

5. There has been a reduced dramatically in the past few years of air pollution.

=>
Ex4/
1. polluted
2. environmental
3. poisoning
4. awareness
5. creatures
6. Chemical
7. speech
8. qualification

Ex5/
1. litter
2. contaminated
3. makes
4. environmental
5. floating
6. from
7. fewer
8. pay
9. noisy
10. to
11. have
12. dramatic
13. action
14. population
15. about

6/
1. E
2. C
3. A
4. D
5. B
Ex7/
1. People will have clean water if we use carefully.

2. A lot of factories continue to dump toxic waste into lakes and rivers.
3. Remember to turn off the light when you don't use.
4. Noise is any sound that loud and constant.
5. How  about planting more trees on streets?

Ex8/
1. If Huong tidied the house, her mum wouldn't feel angry.
2. The more polluted the air is, the more diseases people can get.
3. A lot of underwater creatures die due to the polluted water.
4. We need to use water carefully.
5. There has been a dramatic reduction of air pollution over the last few years.