I often go to school by bike because I think it is one of the best ways of helping to keep our environment.It is also very good for our health because when we ride our bikes,we can exercise and breath the fresh air.I think if lots of people ride bikes instead of driving cars,our environment will be more and more beautiful.What's more,in order to protect our environment,we should use the paper bags instead of plastic bags.We shouldn't spit and litter things.We should put the rubbish into the dustbin.