求英语作文：毕业学生是否应该把课本留给下一届学生使用

For most of the graduates,the used books will be thrown away.But,in order to save the natural resources,we are told to pass the used books onto the students of lower grade.If we keep on doing so,it will help save a lot of paper.Saving paper is to save wood.Then we can preserve more and more forest.Our environment will be better and better.But,when we do so,we have to keep the books clean and tidy so thatthe students in the lower grade can use them safely.