These four titles are a classification of all colleges and universities in China, arranged from high to low.

1. One is a key undergraduate college, which is the enrollment baseline of key universities directly under the Ministry of Education.

2. The second one is an ordinary undergraduate course, which is one grade higher than the first one. Most of the universities with scores from the second place to the first place are also non-key universities, but there are also a few key universities that still have two places and are recruited by a few majors or some majors that focus on this one.

Three books are one grade lower than two. Most of the schools are independent colleges, and the teachers and academic research are one grade lower than the second one.

Four books, which is a special name, generally refers to junior college, with a three-year academic system.