什么是金属材料的力学性能？它包含哪些内容？

A．disposition

B．discrepancy

C．defect

D．deficit

There would be no air pollution to this city because ______.

A．there was a special plant to treat the polluted air

B．the city was away from the mainland

C．people in the city did not burn oil or coal

D．vehicles there were powered by electricity

What two problems can man solve by burning garbage？

A．The shortage of energy and air pollution.

B．The shortage of energy and the land to hold garbage.

C．Air pollution and the shortage of fossil fuel.

D．Air pollution and the shortage of land to hold garbage.

A．Y

B．N

C．NG

It can be inferred from the passage that the sin tax is______.

A．a tax levied to curb unhealthy consumption

B．the most important source of revenue of British government

C．a tax levied on the basis of personal income

D．a tax borne by enterprises rather than consumers

The purpose of the passage is to ______ .

A．describe the harmful air pollution

B．explain the way to prevent air pollution

C．show the worries about the air pollution

D．recommend a method to avoid air pollution

A．A.he cannot understand why people are polluting air and water

B．B.there will definitely be no fresh air and clean water for future generations

C．C.we would run out of air and water if we didn't stop polluting them

D．D.air and water pollution are the current and future state of the environment

A．Trash and garbage

B．Major industries

C．Cars and population

D．Gas fumes and the burning for energy

Air pollution

People and air pollution are often in the same places. This means that cities with large populations have the biggest problem of dirty air. Air pollution is caused by many different things. A major kind of air pollution is the gas from cars. Statistics(统计资料) show that 93 percent of all auto trips are within cities.

Another major kind of dirty air is the burning of coal and oil for energy. This energy is needed to make electricity. Of course, much more electricity is used in the city than in the county.

On the average, we throw away more rubbish than the year before. The burning of rubbish makes air pollution even worse. Many major industries are also responsible for the dirty air in the around cities. The fumes(烟)from iron, steel, chemical, and petrol production add particles(微粒)to the air.

The effects of air pollution range from mild headaches to death. The levels of pollution found in heavy traffic may cause headaches for loss of clear vision. Wherever coal and oil are used for fuel, fumes may kill trees and plants and cause metal to corrode(腐蚀). In some of the larger cities, these fumes endanger the lives of human beings by contributing to lung diseases and causing early death.

26. The key point of the passage is that().

A. the cause of air pollution is people

B. the causes and the effects of air pollution are both found in cities

C. the effects of air pollution range from headaches to death

27. What is the purpose of this passage？

A. to persuade people to stop polluting the air().

B. to tell the causes of air pollution

C. to tell why cities are bad places to live

28. Why is air pollution more grave in the city than in the country？().

A. Because there are larger populations in cities.

B. Because the air in the city is dirty.

C. Because there are much more gas fumes from cars and burning of coal and oil for energy in the city than in the country.

29. The fumes from coal and oil may cause metal().

A. to corrode

B. to twist

C. to turn black

30. In larger cities, the fumes from coal and oil may contribute to().

A. heart disease

B. loss of clear vision

C. lung diseases

Private Cars in China

Key Words: private cars, living standard, discouraged, limitation, air pollution, traffic energy, develop public transportation, raise the price of gasoline