There is no double major, only a minor. You start to register as a freshman. You can study one more major, and you can sign up for a minor in a southwest university (Shanghai Jiaotong University, east china institute of technology, Shanghai University of Engineering Science, Shanghai Theatre Academy, Donghua University, etc.). ) Minors are generally not recognized by the world. It is not utilitarian to say that if you have a special hobby, you can apply for a minor, or you want to study more.

If you ask, it feels a bit casual, but you should usually report it.