精选优质文档-倾情为你奉上ANGLAIS RENFORCE DEC.13.2010TU XIONGPollution of environmentThese days we often hear that our living conditions are getting more and more serious because of the destruction of our environment. It is common that many trees and animals are near extinction, and the all-important food chain has been destroyed. Why does such circumstance occur in spite of social protects? For one thing, the population of the world is increasing so rapid