You can go in. Usually from 7: 30 to 22: 30 in the morning. One teaching, two teaching, three teaching, four teaching and science teaching can be used in all classrooms that are not in class. There is nothing special to pay attention to. Just keep quiet during self-study and don't affect other students. There is no subject category in the study room. There seems to be no other precautions ... pay attention to the safety of personal belongings. ...