EXE II. Combine 

1. If a person looks at the sky at night, he won't be able to see the Milky Way by naked eyes.

2. If noise pollution happens regularly, it will cause stessor nuisance

3. If noise pollution gets more serious in the future, it will affet the development ... society

4.  If Australia invests in water in Vietnamwith good results, half of the population in the rural areas will have access to fresh water.

5.  If you use compact light bulbs, you will save a lot of energy.

6. If we have more space, we will plant more trees.

EXE I. Supply

1. would be

2. didn't go

3. use

4. doesn't want

5. took

6. drive

7. will visit

8. will accept

9. would be

10. would happen

11. got

12. show

13. would be

14. turned

15. will forgive

16. would have brought

17. would have been

18. wouln't have printed 

19. wouldn't buy

20. would drive

EXE III. PUT THE VERBS

1. saw - were trying

2. was walking - felt

3. were driving - appeared

4. was she driving - happened

5. was waiting - came

6. invited - was visiting

7. didn't want - waited

8. rang - was watching

9. began - was sitting

10. went - were having

1. came - were watering

2. was talking

3. was practising - was reading