This may leave you wondering if you should use a colon or a semicolon to connect two independent clauses. Here's a good rule of thumb. If the two clauses are merely related, not necessarily sequential in thought, use a semicolon. However, if the two related clauses follow a sequence of thought, use a colon.
It is okay for students to use cell phones between classes and during the lunch break, as long as they do not create a distraction or cause the student to be tardy for class.