However, man's changes to the physical environment have not always had beneficial results. Today, pollution of the air and water is an increasing danger to the health of the planet. Each day thousands of tons of gases come out of the exhausts of motor vehicles. Smoke from factories pollutes the air of industrialized areas and the surrounding areas of the countryside. The pollution of water is equally harmful. The whole ecological balance of the sea is being changed and industrial wastes have already made many rivers lifeless.
Now environmental protection is more pressing than ever before. As we know, massive destruction of environment has brought about negative effects and even poses a great threat to man's existence. Indifference to these problems will mean committing suicide. Therefore, effective measures should be taken and laws passed to conserve environment. Otherwise,man is certain to suffer from the serious consequences caused by this lack of care for his living surroundings.
Water pollution 水源污染
Water is used in homes, in farming, and in manufacturing. The water used by the people comes from oceans, lakes, rivers, and streams. Many water sources are becoming polluted. People are throwing things into the water. Factories are dumping waste materials into the water. Cities are dumping sewage into the water. Some water sources have become so badly polluted that the water cannot be made fit to use. Would you like to drink water that came from a source that had been so badly mistreated? Now is the time that we should take up our responsibility to protect our environment from being polluted.