根据短文内容回答问题，每空一词。

     Every day some people are killed (遇车祸) while they are crossing the roads. Most of these people are

old people and children. Old people are often killed because they can't see or hear very well. Children are

killed because they are not careful. They forget to look and listen before they cross the roads.

     A car or a bus can't stop quickly. If a car is going very fast, it will travel many meters before it stops.

Some people don't always understand this. They think a car can stop in a few meters. It is difficult to know

how fast a car is moving. The only way to cross the roads safely is to look both ways, right and left. Then

if the roads are empty, you can cross them.

1. Why are old people often killed while they are crossing the roads?

    _________ they can't see _________ hear very well.

2. Do people think a car can stop in a few metres? 

    _________, they _________.

3. Children are often careless while crossing the roads, aren't they?

    _________, they _________.

4. What should we do before crossing the roads?

    To look _________ _________.

5. When can you cross the roads?

   The _________ are _________.