Most people like bikes. Perhaps you ride a bike to school. Riding a bike can be great of fun.Do you know how to ride a bike safely?

    Careful boys and girls learn to ride their bikes well before they go out on the road.How can you tell whether you are a good rider?

    If you can ride a bike in a straight line,you can ride well .If you can't ,you should practice riding a in a safe place.

    To be safe on a bike, you need to use both hands and both feet. Keep your feet on the pedals(脚蹬)and your hands on the handle bars.

    You know that your bike is only for one person. It's not safe to carry anyone with you. Keep yourself safe when you ride on a bike.Watch where you are going all times.

人走路时，脚被石头绊住，由于____ ，上身仍要保持原来的____ 状态，而向____ 倾倒．

唐朝时实行三省六部制，三省之间分工明确，办事效率高。如果当时要制定税收政策，程序应该是