【单选题】Mark was a student at this university from 1999 to 2003, _______ , he studied very hard and was made Chairman of the Students' Union. A. during which time B. for which time C. during whose time D. by ...
【单选题】During the voyage he encountered boisterous winds and heavy weather during which time the vessel________ heavily and to such an extent that at times it was necessary to change course.