quick, while , clear, meter, walk, cross，both，carefully, wait, understand

Many people die from accidents every year. Nowadays road accidents happen very often. People are often killed     crossing the road. Most of these people are old people and children. Old people are often killed because they usually cannot see or hear very well. Children are often killed because they are not    .A car, a truck or a bus cannot stop very    . If it’s running very fast, it will travel many meters before it stops. People don’t always     this. They think a car can stop in a few   . The faster a car traveling, the longer it takes to stop.
The only safe way to cross the road is to look     ways, right and left. Then if the road is    ,it is safe to cross. The right way to cross is to     quickly. It’s dangerous to run. If people run   the road, they may fall down. besides, we can’t cross the road when the traffic light is red. We must   until the light is green. If old people have trouble in crossing the road, young ones should try their best to help them.