What must not you do when you're in the school buildings?

What do you think about the buildings in Beijing? Do not know what you're talking? what can you do and what can not you do in your school lab You must not pack your school bag when you hear the fire bel When do you usually s__ your school in the morning When do you usually l____ school in the afternoon Which school are you in?When you study?What do you want to d What should you do when you're tired?（急!） Must you do not What can you do in the school show? what must you do when you change lanes什么意思 What should you do when you're tired?和What should you do whe