III. Fill in each blank with one suitable word. (1,5pts)
1. It's possible to..............solar energy for a nümber of days.
2. Solar energy doesn't cause.................
3. If we go on............... our environment will become seriously polluted.
4. A..................is a person who works to protect the environment from damage or destruction.
5. If we keep our environment clean, we will live a happir and..............life.
6. My friend....................taking showers because we can save water