First of all, the little problem you mentioned: sophomore to junior can apply as long as they don't fail the course. At the end of the freshman semester, the secretary of the League branch of each class will show the students the professional catalogue of minor majors. As long as you have a subject you want to study, you can study it. One credit 60 yuan, free choice of academic system. The longest is two years and the shortest is one year. After graduation, I obtained a minor certificate from Yangzhou University, which is equivalent to a junior college diploma. If you miss the class declaration, you can go to the academic affairs office of the college you want to study. Money has to go to the school finance department to teach, please!
If the major you want to study is not provided by Yang Da, you can apply to other schools. For example, universities in Nanjing do not have the right to award double degrees, while many universities in Nanjing can. The general academic system is also two years, and most of them attend classes on weekends. You can be diligent at all, and it is more useful to get the second bachelor's degree certificate from the school.
Serious statement: there is no such thing as a double degree certificate! Sweat ~ this is not the two-in-one essence of shampoo, they are developed separately.