Là, ấy là

only one student passes his examination, namely AN

chỉ có một sinh viên thi đỗ, ấy là AN

Specifically, to wit, that is (to say), id est, i.e.,videlicet, viz., scilicet, sc.; for example, for instance,exempli gratia, e.g. or eg or eg.: We visited three countries,namely, France, Italy, and Switzerland.

That is to say; in other words.