Is there any reason why the teacher can return my mobile phone to me on Friday? It must be very reasonable. The kind that makes the teacher unable to answer back.

How long has the teacher been holding your mobile phone? How old are you? What is your self-control? If your mobile phone has been confiscated for a long time, you can ask the teacher to get it back, but you should control the time to play with it. It's best not to play in class, let alone study at night. Your task now is to study hard. You can go home this weekend, then put your mobile phone home and never take it again.