1. Unless you study hard, you won't pass the exam.

2. Because factories produce waste and pour into rivers and lakes, many rivers and lakes are poisoned.

3. After they provided food, they cleared up the debrish.

4. Many natural disasters have been caused by global warming.

5. We had just got on the plane, the pilot told us to get off again.

6. Peter asked his colleague not to open the laboratory that day.

7. Phong asked Dr Nelson if the Earth would ever be visited by aliens.

9. If she were a millionaire, she could buy a house in Tokyo.

10. If I were you, I would recycle these plastic carrie bags.

- Thieukhue -

＃ＳｕｎＨｕｙｎ