Every day some people are killed 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（）very well．Children are killed because they are not（）．They forget to look and listen before they（）the roads．A car or a bus can’t stop（）．If a car is going very fast，it will travel many metres（）it stops．Some people don’t always understand this．