2. In the same way, most school libraries can enter and exit at will, and some schools need vouchers to enter, such as credit cards, student ID cards and teacher ID cards. The speech depends on where it is. If it is held in the classroom, you can enter at will. In the library or special non-teaching building, the kind that is not open to the public is not acceptable. You can still learn a lot from lectures. Of course, there are also many lectures in the university. How to obtain lecture information is as important as how to filter it. Don't waste time unnecessarily.

I'm sorry I didn't take the self-study exam, but if I really want to take it, I still need to find some authoritative people or books or websites to understand clearly.

Wish you success!