It is undeniable that the worsening environment has become the biggest concern of the present-day world.Land resources are dwindling because of water loss and soil erosion.Waste gases poison the air we breathe. The rivers and lakes are polluted by waste dumped in them from factories.It is probably no exaggeration to say that deterioration of the quality of the environment threatens the existence of mankind itself.

　　不可否认的是环境恶化已成为当今世界上人们最担心的事了。因为水资源的浪费和土壤被侵蚀，土地资源逐渐缩小。我们呼吸着有毒的空气，河流和湖泊也被附近的工厂里排放出来的废弃物严重污染了。不夸大其词地说，环境质量的恶化很可能威胁人类的生存。