The first choice is the first choice of institutions reported by candidates in each admission batch, which is often the most ideal and eager choice for candidates to be admitted. The first choice is that in each admission batch, the admissions department first sends it to the admissions school for candidates to choose.
Postgraduate is a kind of qualification certification of national education, which is generally carried out by ordinary universities with master's and doctoral degrees. You can also be called a graduate student after graduation, which means someone with a graduate degree.