We can't laugh blindly (they are absolutely wrong on this point).

We must abide by the school system.

We can't be late for class.

We must clean the room every day.

We must wear school uniforms every day.

We must keep the classroom clean and tidy.

You can't drink food in the library.

We must line up in the corridor, don't be crowded.

10 This road in our city is usually very busy.