It's not easy to get a postgraduate diploma in the 1990s. Postgraduates in the 1990 s were not easy to take the exam. In that era when higher education has not expanded its enrollment, it is already a very good achievement to be admitted to the undergraduate course, and it is one in a thousand to be admitted to a key university. Similarly, there are not so many people who are willing to continue their studies after graduation. In that era when the pressure of employment competition was not as great as it is now, there were not many undergraduate places, and even fewer graduate places.