Scientists and environmentalists have repeatedly warned us of serious environmental problems such as water and air pollution, water shortages, diminishing natural resources, toxic wastes, and deforestation.

• 科学家和环保主义者一再告诫我们所存在的严重环境问题,例如水和空气的污染、水资源的短缺、缩减的自然资源、有毒垃圾以及砍伐森林。