5. environmental protection

　　today the quality of our natural environment has become an important issue. the world population is rising so quickly that the world has become too crowded. we are using up our natural resources and at the same time polluting our environment with dangerous chemicals. if we continue to do this, life on earth cannot survive.

　　concerned people have made some progress in environmental protection. governments of many countries have established laws to protect the air, forests and sea resources and to stop environmental pollution.

　　still more measures should be taken to solve environmental problems. people should be further educated to recognize the importance of the problems, to use modern methods of birth control, to conserve(保存) our natural resources and recycle(再循环) our products. we are sure that we can have a better and cleaner place in the future.

　　6. automobiles

　　automobiles, as a product of modern civilization, have been playing a vital part in the daily activities of human society. industry needs automobiles for farming as well as transportation. every day, automobiles drive people to and from work. on weekends automobiles take families for joyful outings. and during holiday seasons, automobiles fill the highways everywhere, even in remote areas. it could be said that the wheels of automobiles move society forward.

　　but automobiles have also given rise to a series of problems. for example, cities are overcrowded with automobiles. they create a lot of noise and traffic accidents which disable(伤残) or kill many people each year. worst of all perhaps is the air pollution caused by the exhaust gases produced by automobiles. some of the gases are highly toxic(有毒的) and a serious health hazard.

　　7. computer

　　the computer is widely used in all fields of society. today, wherever you go, you will find computers being used. for example, computers are used in universities, large corporations, and small Offices, etc. it has even entered the homes of ordinary people. as it is able to store and process a large amount of information, the computer bring about great convenience and high efficiency to people of all walks of life.

　　computers can help people in different ways. for example, computer help scientists in analyzing data and doing complex calculation. for another example, computers are made use of by engineers in designing a plane, or a spaceship. besides, computers may also play a great role in helping children with their lesson. whatever you are doing, you many find computer a useful aid.

　　however, the computer must be designed and instructed by man. what is more, it is true that computers can make decisions, but they need detailed instructions and programs prepared by humans to operate. therefore, the computer can never replace the human brain.