A few days ago, I went to the railway station to see my friend off. On the way I saw street-cleaners burning dry leaves. What they do is wrong.

　　Burning things does harm to people. I remembered that our teachers once told us that burning dry leaves would give off smoke and dust which in turn pollute air. And what is more, it would be harmful to people's health. When people breathe the air with smoke, the smoke might lead to cancer. As a result, the cancer would cause people to die.

　　As we all know, leaves can make very good fertilizer. It would be better to collect them for the fields.