As far as I know, vocal music graduate students don't have a set of songs, only that they have certain requirements, such as opera aria, art songs and Chinese songs (bel canto)! It is required that the coverage of the five songs should be wider. If you are a folk song, you should divide it into traditional folk songs, create songs and adapt them from traditional folk songs. This is mainly to look at the enrollment brochures of each school carefully and clearly.