Throughout history man has changed his physical environment in order to improve his way of life. With the tools of technology he has altered many physical features of the earth.

纵观历史，改善自己的生活方式，人类已经改变了自然环境。人类借助技术工具改变了地球上的许多自然特征。

He has transformed woodlands and prairies into farms and made lakes and reserviors out of rivers for irrigation purposes or hydroelectric power. Man has also modified the face of the earth by draining marshes and cutting through mountains to build roads and railways. 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.

人类将林地和草原改造成农田，河流湖泊和水库里面的水用于灌溉和水力发电。人类还通过排干沼泽和开山修建公路和铁路来改变地球的面貌。但是人类对自然环境的改变并不总是带来有益的结果。 今天，空气污染和水污染越来越威胁到地球的健康。每天，成千上万吨废气从车辆的排气管排出。工厂释放的烟雾污染了工业区的空气和周围乡村。水污染也是同样的有害。整个海洋生态平衡正在改变，工业废水已使许多河流死气沉沉。现在，环境保护比以往任何时候都更紧迫。我们都知道，环境的巨大破坏已带来负面影响，甚至对人类生存带来巨大的威胁。

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.

对这些问题漠不关心意味着是自杀行为。因此，应采取有效措施并通过法律来保护环境。否则，人类一定会遭受因为不关心自己所居住的生活环境而造成的严重后果。