1.We should keep our Earth clean. We don't make any terrible  (pollute).

2.What will you be like in twenty  (year)time?

3.I live on the   (twelve)floor, so I go up and down by lift every day.

4.We usually have three  (meal)a day.

5. After you finish  (write)the report, please come to my office.

6. People will be able to understand each other  (well)if they speak the same language.