Often people say 1A, 2A, 3A, 1B, 2B, 3B means the grade of the university, 1 on behalf of the Ministry of Education approved the key universities that are usually referred to as a school. 2 on behalf of the non-focus on the university that is the general undergraduate university that is usually referred to as a two-book school. 3 on behalf of the three-book colleges and universities. And A,B refers to the same type of school grade.
So 2A is said to be the second school in the better schools;
And 2B refers to the second school than the A class school and then a lower grade of the school, but certainly 1B than 2A school in some good. For example, the University of Mines, the University of Petroleum, and so on.