Bicycles are welcome by the people who love sports.But ,with more and more pollutions,especially the air pollution,we should ride bikes more oftenly.First of all,we can reduce the traffic accidents by riding bicycles.Secondly,riding bicycles can save energy which is becoming less and less.And the third,perhaps,the most important is that riding bicycles can help protect our environment.That is why more and more people begin to use their bicycles to work,to schoo or to anywhere they like.And they think that it is also a good sport which can make people much more healthy.