There are corresponding subject codes for the first test subjects of postgraduate entrance examination, of which 3 1 1 is the comprehensive subject code for the national unified examination of pedagogy, and other codes are the self-made subject codes for the enrollment units. Extended information postgraduate entrance examination generally refers to the national unified postgraduate entrance examination. National unified entrance examination for graduate students, referred to as "postgraduate entrance examination". It refers to the general name of the relevant examinations organized by the education authorities and enrollment institutions for the selection of graduate students, and consists of the initial examination and re-examination organized by the national examination authorities and enrollment units. This is an optional exam.