1, There aren’t many students taking part in the event.

2, They moved to here two years ago.

3, If you don’t turn unwanted lights off, you will waste a lot of electricity.

4, Why don’t we write about the three Rs?

5, It’s fun to learn about recycling.

6, Reusable bags are more expensive than plastic bags.

7, You should not throw old clothes away.

8, Don’t forget to turn the tap off when you are brushing your teeth.