With the development of scientist, we have air ,car,train and so on. It's convinet for us ,we can go further than former. But as you know, we paid for our action . sea level has raised , air become badly.Chemicals were poured into river , caused sealife lost its life. I belive in punished next is human beings. So I think we should protect environment from pollution.It's our duty. It's no need drivering. we can ride a bike. Riding can benefit us.For example, while riding , we can see beatiful flowers and trees. we can know something we don't know.we can chat with everyone, too. The important one ,riding a bike is enery saving and benefit our health. Besides,It's best way of low-carbon life.