When the holidays came , some problems were happening . Two of the biggest are heavy traffic and pollution .

　　In the cities . There are many cars and bikes . So that cause heavy traffic and pollution . On the road . When you are riding a bike , think about the risk of an accident .

　　There are some advise . Obey the traffic rules , when the lights were chancing to green , you can go . Don't ride so fast , when it was raining . In the home , keep clear of fairs . Don't play in the kitchen . After you watch TV , you should turn off the TV .