1. Because factories produce waste and pour it into rivers and lakes, many rivers and lakes are poisoned 2. My bicycle has been stolen 3. That old house has been just sold by them 4.If teacher teach environment issues at school, students will be more aware of protecting the environment 5. He said that they was doing an experiment 6. English is spoken all over the world 7. If i had free time, i would go with you 8. After they had provided food, they cleared up the debris

1. Many rivers and lakes are poisoned because factories produce waste and pour it into them.

2.  My bike has been stolen. 

3. That old house has just been sold…

4. If teachers teach environmental issues at school, students will be more aware of protecting the environment.

5. He said that they were doing an experiment then.

6. English is spoken all over the world.

7. If I have free time, I can go with you.

8. After clearing the debris, they provided food.

`Jeikei`