n.降格；堕落；退化
Slow degradation of ground water quality may result from repeated use. 循环使用地下水可以导致缓慢的水质降低。
Gambling is always coupled with degradation . 赌博总是与堕落相联系。
Environmental degradation is a global issue of common concern to the international community today. 环境恶化是当今国际社会普遍关注的全球性问题。
n.生物降解
