答案:参考范文:There used to be a river in my hometown, in which fish were swimming happily. Whenever I saw it, I couldn't help thinking of my happy childhood. But now not only are there no fish left but also it gives off a terrible smell. It is said that it was a chemical factory nearby that made the river so seriously polluted. I think it's high time that the government took measures to stop it from being polluted. Only when we have blue sky, white clouds and clean water can we live a happy life.