First, there are many people. Take the college entrance examination as an example. It is really difficult for millions of candidates to use their usual grades. However, this problem can be solved slowly through the unification of national student information.

Second, the educational resources in different regions are unbalanced. Children in developed areas do enjoy more educational resources than children in underdeveloped areas, and their academic performance is much better. If the whole country is unified according to their usual achievements, it is actually unfair. Children in developed areas have good academic performance, but there is great competition. In this way, students in underdeveloped areas will have advantages, which can be made up by constantly integrating educational resources, but it takes time.

Thirdly, it is very important that China's human society is very easy to operate if it is admitted according to its usual grades. As long as you have a good relationship with the teacher, you can completely control the score, which is the most difficult to solve. There are so many disadvantages just looking at the policy of protecting research. If the college entrance examination is the same, it is likely to be more unfair and difficult to solve.