阅读与回答问题（本题共5小题，每小题2分，满 分10分）请认真阅读下面短文，并根据短文内容回答问题。
Young children don't have the skills or knowledge to stay safe in heavy traffic. The following advice will be helpful for you to keep your children safe in heavy traffic.
Children learn about road safety by watching others. Make sure that you always set good examples. Your children will follow you and think it's OK to do like you. Teach your children to pay attention to traffic lights when you cross the road together with them. This helps them understand when it's safe to cross. Make sure that you walk between your children and traffic, and hold their hands all the time.
When your children are a little older, you can start to tell them the importance of traffic knowledge. Let them start to understand the reasons why they need to be so careful. Talk with them about road signs and traffic rules.
Ask your children to play in a safe place. Never let them ride bikes on the road without an adult present at rush hours.
The most important thing you can do to keep your children from getting hurt is to encourage them to follow traffic rules.  After knowing about traffic rules, they'll volunteer to obey them. In this way, they'll be careful enough to keep themselves away from danger.
Who should set good examples to young children on roads?
                                                                           
What should children pay attention to when crossing the road?
                                                                           
When should young children never ride their bikes alone on the road?
                                                                           
What should children learn about traffic when they are a little older?
                                                                           
What is the writer's purpose of writing the passage? (请自拟一句话作答)