You can sit in as long as you are willing to take the time to listen.
3. How can I skip class? Arranging such courses has the school's own ideas. What we need to do is to adapt to these courses. If you are not interested, you can teach yourself.
4. Up to 4 classes a day (excluding the possibility of self-study in the evening), one class lasts for 2 hours, with breaks in the middle.
The exam includes the courses you studied this semester, and some of them are practical homework. Don't worry about too many exams.
6. If you apply for this major, the school teacher will make corresponding arrangements. Don't worry. If you still need to expand, you need to check the elective courses yourself, and the general elective courses will be similar.
If it is profit-driven, you need to arrange it yourself. There must be some related documents in the library for your reference.