根据短文内容，完成下列各题。

    Fire can start in forests, homes and schools. It is very dangerous. What should we do when there is a fire? We should go outside quickly. And we have a fire drill at school every year.

    A fire drill is not a real fire, It helps us prepare for(为……准备) a real fire. This map tells us the way in a fire. We can follow the fire exit(出口) signs too. First, the fire alarm sounds. Next, we all line up and go out quickly. We leave all our things in the classroom. Then we walk down the stairs and go outside. We line up in the playground. Our teacher checks on the number of students. We should wait for the firemen to come.

生物体的构成，就像建房子一样，它是由细胞、组织、器官、系统等不同的层次构成的一个统一整体．通过两年的学习，关于生物体的结构层次，我们应该有了一些新的认识，形成了一些新的观点．