Throughout history man has changed his physicai environment in order to improve his way of life.With the tools of technology he has altered many physical feathures of the earth.He has transtormed woodlands and prairies into farms and made lakes and reservoirs 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 everbefore.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.
译文：人类有史以来不断改变自然环境，以改善自己的生活方式。人类借助技术工具改变了地球的许多自然特征。他将林地和草原改造成为农田，使江河变成湖泊和水库，用于灌溉或用于水力发电。人类还通过给沼泽地排水、凿石劈山、修建公路和铁路等方式，改变了地球的面貌。
然而，人类改变自然环境并不总是带来有益的结果。今天，空气和水的污染给地球的健康造成越来越严重的危害。每天机动车辆的排气管排出成千上万吨废气。工厂释放的呀呢污染了工业区和周围乡村的空气。水污染同样有害，海洋的整个生态平衡正在受到破坏，工业废水已经使许多河流的生物死亡。
现在，环境保护比以往任何时候都更为紧迫。我们知道，对环境的大规模破坏已经带来负面影响，甚至严重威胁到人类的生存。对这些问题漠不关心将意味着自我毁灭。因此，应采取有效措施并通过法律来保护环境。不然的话，人类势必遭受因其不关心生存环境而引起的严重后果之苦。