You can't. The narrative of the exam composition will get zero when it is written as an argumentative essay, because it does not meet the composition type of the topic. You can't write a narrative in an argumentative essay for postgraduate entrance examination. Postgraduate entrance examination generally refers to the national unified postgraduate entrance examination, which 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.