请给出每道题目的详细思路,Students are always interested in finding out _______ they can go with a new teacher.

请给出每道题目的详细思路,Students are always interested in finding out _______ they can go with a new teacher.
A.how far B.how soon C.how often D.how long
Fred entered without knocking and,very out of breath,sank _______ a chair.
A.on B.off C.into D.to
Modern equipment and no smoking are two of the things I like ____ working here.
A.with B.over C.at D.about
Elizabeth has already achieved success _________ her wildest dreams.
A.at B.beyond C.within D.upon