4. 环境污染问题
Pollution has become a social problem in today's world because people in an increasingly populated and industrialized world are polluting the environment in which they live. The growing population increases the demands for the world's limited water and land. This rise in population is followed by more and more people's desire for a better standard of living. So the greater need for electricity, water and merchandise will inevitably bring about more waste materials that need to be disposed of. The problem has raised increasing concern for creatures and their environment.
在当今世界，人口越来越多，社会也越来越工业化，生活在这种条件下，人们在污染着自己的居住环境，因此污染已经成了一个社会问题。人口增长增加了人们对世界上有限的水和土地等的需求。随着人口增长，越来越多的人渴望更高的生活水平。于是对电、水和商品的更大需求必然导致更多的废物需要处理。这个问题已经引起人们对生物及其环境的日益关注。
