Section 3.
Task 1. Learning to rephrase.
1. In the United States, we are using more and more oil everyday, and the future supply is very limited.
2. It is estimated that at the current rate of use, oil may not be a major source of energy after only 25 more years.
3. We have a lot of coal under the ground, but there are many problems with mining it, transporting it, and developing a way to burn it without polluting the air.
4. Production of new clear power plants has slowed down because of public concern over the safety of nuclear energy.
5. The government once thought that we would be getting 20% of our electricity from nuclear energy by the 1970's,
but nuclear energy still produce only about 12% of our power as of 1979.
6. There is no need to purchase fuel to operate a solar hearting system because the sunshine is free to everyone.
7. Because solar system depend on sunshine, they can't always provide 100% of your heat.
8. Solar heating can be used in most areas of the United States,
but it is most practical in areas where there is a lot of winter sunshine, where heat is necessary, and where fuel is expensive.
9. A hot-liquid system operates in basically the same way except the hot-liquid system contains water instead of air,
and the storage unit is a large hot water tank instead of a container of hot rocks.
10. The energy from the sun may provide the answer to our need for a new, cheap, clean source of energy.