用方框中所给单词的适当形式填空，使短文通顺、正确、连贯（每个单词限用一次）

School is where we learn, make friends and grow up. But ______ happen daily in schools across the world. We hear reports of students falling down _____ buildings while cleaning windows. Other students are hit by football on the playground. Three years ago, some students fell down on the stairs and were stepped on by___, with tragic results.
We feel ______ sorry for the loss of lives. There is _____ we can do to bring the students back, but we can try to prevent (防止) such things from ___again. You should do the following things to prevent a stampede (踩踏)。
After class or school, don’t rush out at the same time. Wait until there are ______ people trying to leave.
When you walk with a crowd of people, stay alert (警惕的) and _______ your steps. Don’t play around。
Be familiar with your ____ and learn where the safety exits are.
When there’s pushing and squeezing (挤)， don’t move and try to hold on to something. ____ stay in a corner until the crowd leaves.