Peking University can register with its ID card, but it is quite easy to get in when it is not on holiday. If you look like a student and come out of the south gate with a schoolbag on your back, you can look straight ahead and pretend that you didn't see the security guard striding in, and the security guard won't stop you. (At your own risk ...) All classes of Peking University can be found in official website. Theoretically, if you have the curriculum of Peking University, you can take any class, but it should be noted that language courses are generally not allowed if they are taught in small classes. You don't want to listen to physical education class, do you? In addition, as long as you don't disturb other students, (don't casually strike up a conversation) and disturb the normal order of the classroom, no one will say anything and no one can see that you are listening. In fact, most students believe that you are a moderate observer = = Note that if you want to eat, you can use WeChat cash to go to the supermarket or coffee shop in the school, and never stop students from borrowing cards in the canteen ... (There are often complaints on BBS that strangers outside the school have mixed into the classroom of Peking University to disturb the order and harass students, so students may be unfriendly to outsiders)

(I thought about going to Peking University before I was admitted = =)