In fact, for students in Tsinghua, especially students in science and engineering, there is almost no concept of postgraduate entrance examination. The destination of undergraduate graduates in Tsinghua is mainly for further study, promotion and direct scholarships on campus, and they don't need to take the postgraduate entrance examination.
Tsinghua's postgraduate entrance examination rate is so low, because there is a vast blue ocean to choose from, and most students don't need to squeeze the wooden bridge to take the postgraduate entrance examination.
For students who go abroad, not everyone can apply to the top schools in the world, but it is not difficult to apply for a full scholarship from a second-rate university in the United States with a letter of introduction from a teacher and several years of academic achievements and scientific research experience in Tsinghua, as long as TOEFL and GRE pass.