III. Put the verbs in brackets into the correct form.

1. If he (study) harder, he can pass an exam.

2. She may be late if she (not hurry)

3. If you study harder, you (pass) the exam.

4. If people really cared about the environment, they (not dump) waste into the lake.

5. If there was no fresh water in the world, what (happen)

6. If you (be) the president, what would you do to help the environment ?

7.They get sick so often.If they exercised more, they (be) healthier.

8. If I (have) one million US dollars, I would build more parks in our city.

9. Four countries (visit) by John so far.

10. London (have) a population of eight million people.

11. Vietnams Independence Day (celebrate) on September 09th.

12. We (visit) Sydney Opera House for several times.

13. Some activities (prepare) to celebrate the lunar new year now.

14. When I came to the stadium, the match (start)

15. Before she (listen) to music, she (do) homework.

16. Last night, Peter (go) to the supermarket before he (go) home.

17. Most students (leave) before the volcano (erupt) .

18. I (find) my pen after I (buy) a new one.

19. Food and medical supplies (deliver).yesterday afternoon.

20. In the future, natural disasters (predict) accurately with the help of technology.

21.Three cats (rescue) .by the volunteers last Sunday.

22. Two houses (build) .in the city every years.

23. Earth (hold). by the gravity of the sun and orbits around it.