Xiao Chen was refused entry to the ancient book library by the staff because he did not have the status of a graduate student. Xiao Chen showed the pass of the rare book library of ancient books and said: According to the regulations, I can enter the ancient book library. The rule of it is that non-graduate students are not allowed to enter the ancient book library, and only those who have a pass for the pass of the rare book library of ancient books can enter the rare book library of ancient books.
Xiao Chen's understanding of the rules of the ancient book library is that if you have a pass of the rare book library of ancient books, you can enter the ancient book library.