1. Competitive pressure: As a top institution in China, the postgraduate education of Zhejiang University has a high popularity and attraction, thus attracting a large number of outstanding students to apply. This makes the competitive pressure of re-examination relatively great, and candidates need to have excellent academic background and comprehensive quality to stand out.

2. Investigation of professional knowledge: Postgraduate re-examination usually involves an in-depth investigation of candidates' professional knowledge. This undoubtedly increases the difficulty for candidates with weak cross-disciplinary or professional foundation. For some popular or research-oriented majors, the inspection may be more difficult.

3. Comprehensive quality inspection: In addition to professional knowledge, the postgraduate re-examination will also examine the comprehensive quality of candidates, including expression ability, logical thinking ability and teamwork ability. The performance of these aspects will also affect the candidates' retest results.