III.
1. Shall we buy energy-saving bulbs?
2. Why don't we turn off the faucets?
3. I suggest walking to school.
4. I suggest taking a short rest.
5. We suggest using electricity economically.
6. That tree was planted 5 years ago.
7. I suggest using gas instead of burning coal?
8. Because Tom was lazy, he failed the exam.
IV.
1. and
2. however
3. and
4. so
5. therefore
V.
1. He was thirty, so he drank a lot of water.
2. He was intelligent, but his father was worried about his performance.
3. It rained, so we decided to postpone the picnic.
4. We stayed at home and we watched TV.
5. She passed the exam because she studied hard.
VI.
1. You should reduce the amount of electricity your family uses