假如昨天下午全校师生进行了一次地震逃生演练（a practice of escaping from an earthqu

One possible version:

Yesterday morning, our school gave us a practice of escaping from an earthquake. All the teachers and students took part in the activity.

Before it, our head teacher , Miss Wang, told us the rules for escaping again. It started on time at 8:00 a. m. Miss Wang shouted,“Under your desk!”All the students stayed under the desks with arms covering the heads. Next, she shouted“Group One, go!”… “Group Two, go!”…. My classmates ran out of the classroom one after another. When I was walking on the right down the stairs, Lucy in front of me fell down suddenly. I held her up quickly. All of my classmates got to the playground at 8:01. No one was left.“We only spent one minute.”said Miss Wang happily.

This activity is popular with both parents and students. We learnt a lot from it.