Writing prompt: How to Treat the Evacuation Drill?

Student essay:
Today my speech topic is how to take part in evacuation drill.In our shool,every term will hold the evacuation drill.It was known to all that this activity wants to teach us how to face the dangrous situations.It aiso can teach us some knowleges and skills in these aspects and improve our abilities to protect and save ourselves.
Nevertheless,when this activity was helding ,students are not serious about this.For example,sometimes students are going to laugh and talk loudly.So,in my opinion we should keep calm and quiet,listen to the signs about drill.
My speech is over.I hope you can take my advice.Thank you!

Corrected essay:
Today my speech topic is how to take part in an evacuation drill. In our school, every term we hold an evacuation drill. It is known to all that this activity wants to teach us how to face dangerous situations. It also can teach us some knowledge and skills in these aspects and improve our abilities to protect and save ourselves.
Nevertheless, when this activity is held, students are not serious about it. For example, sometimes students laugh and talk loudly. So, in my opinion we should keep calm and quiet and listen to the signs about the drill.
My speech is over. I hope you can take my advice. Thank you!