Our factories and homes burn coal and oil. Every year we have forest fires somewhere. Many scientists believe that the climate is changing.
The earth will perhaps be warmer by about 7 degrees centigrade. At the South Pole and the North Pole, the ice will melt (融化). The sea level (海平面) will rise by about 7meters. As a result, water will cover cities like London, Tokyo and New York. Some ports and towns along the coasts will disappear under water.
Some other scientists think that the dust, smoke and pollution from coal, wood and oil fires will block out the sunrays(紫外线). Then the earth will become colder and great sheets of ice will cover Europe and North America.
When chemicals in the air mix with rain, we have acid (酸) rain. Acid rain can bring us great harm. It destroys forests and kills life in lakes and rivers.
People are beginning to see how serious the problem is. They find it important to work with nature instead of against it. They are trying to save the earth in many different ways. But one of the most important things to do is to make people understand that saving the earth is saving ourselves.
Some scientists believe that          .               
A. the earth is growing warmer
B. we can find oil in our forests
C. we have to burn down the forests every year
Ice at the poles will          if the earth gets warmer.
A. cover cities like London and Tokyo
B. raise the sea level by 7 degrees
C. become water and make the sea level rise                
Acid rain          .
A. brings great changes in our climate
B. kills pests in lakes and forests
C. kills the fish in rivers and lakes                        
What can we learn from the third paragraph?
A. The dust together with pollution from coal, wood and oil fires will bring us more heat from the sun.
B. The sunrays will come more because of the dust and pollution from fires.
C. As a result of the dust and pollution from coal, wood and oil fires, the earth will become colder.                                                                  
Which statement is TRUE?
A. People have come to know the importance of working with nature.                
B. All the scientists agree that our earth is sure to become warmer and warmer.
C. The sea level will rise if the earth gets colder.