City environment is very important for us so we should keep it clean .First good environment is good for our health.Besides,it will also make an impression on the tourists,which will certainly influence the populatity of the city.So we should take measures to protect our environment.First we should set up some board saying something like protecting environment.Make all the public aware of the importance of the environment to us.Second we should plant more trees to make our city more beautiful and greener.And trees can absorb poisonous gas from cars and factories.I think only in this way can we have a greener and cleaner city.