Of course, we don't have to pay it. Mobile phones are used to help us study. We can download all kinds of software and practice all kinds of knowledge we want to learn. Moreover, we are all adults in college and have a certain degree of self-control, so we can contact our families by mobile phones. Check the bed to make sure that we are all in the dormitory, for fear that it is not safe for us to go out at will, which is also for our safety.