If rich countries spend more money on green industries instead of building military machines and making nuclear weapons, many pollution problems that are common today will gradually disappear.

2. Burning coal not only consumes oxygen in the house, but also emits toxic gases.

3. Obviously, finding alternative energy sources is very important for the stable development of China's economy.

4. Solar cells can absorb sunlight and convert it into electric energy.

5. If the earth's temperature continues to rise year by year, the polar ice caps will begin to melt, and half of the buildings in coastal cities are likely to disappear under the waves of pipa dancing.

6. Because these small leaves are often hidden under dense vegetation, they are not visible to the naked eye.

Due to atomic radiation, he finally fell down at work.

8. There is clear evidence that weight and physical work are related to some diseases.