In recent years,we have sand storms in the north part of China much more oftenly.And the sand storm has brought us much more inconvenience.The sky is full of dust and dirt and people cannot easily go out or work outside.The reason for the sand storm is that people have raised more and more sheep and cows and they live on the grasses,even the roots of the grasses.Meanwhile,people have paid no attention to the preservation of the environment.They cut trees in the forest.All these lead to the result that the field has been changed into dessert and the soil has been washed out by heavy rain.At present,government has put stress on the protection of the environment with more and more investment.Everybody should do something with it so that we can have a clear and clean homeland.