You can introduce yourself to the teacher before class, tell the teacher why you want to listen, praise him, say that you are interested in this course, and hear others say that the teacher speaks this course best, so I want to listen. Many students skip classes, and the teacher will not let you go if you come to listen to them specially across disciplines. It's too late to be happy

Then you should communicate with the monitor of this class. If you have friends in this class, please ask them to take you to talk to the monitor. If not, talk to yourself. Don't treat the monitor as an improper cadre. If the monitor doesn't let you, you can hardly learn anything in this classroom.

Counselors will call the roll from time to time Counselors basically won't let people from other departments come to their classes, mainly because they are afraid that the people coming will be the boyfriend and girlfriend of someone in the class, which will affect class and discipline. You should understand the counselor. So you'd better let the teacher tell you in advance and let him tell the counselor about you. Counselors basically give teachers face. Of course, you should communicate with the counselor yourself and tell him that you are not here to make trouble, but really to study. In this case, he has no reason not to let you attend class.

In short, you have to communicate with teachers, monitor and counselors. You can't go to other people's classes without saying a word. It will be difficult to explain then, and it will be too embarrassing to be kicked out. Finally, you really have to learn, because you are too high-profile, and all eyes are on you. If you are not serious, the teacher will be the first to pick on you.