问题
选择题
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 that time
答案
答案：A
考查介词与关系词引导的定语从句。先行词是1999 to 2003, 因此应选择A，在这段期间。