问题补充:
There are two thousand students in this college, are from the countryside.
A. one-third of them
B. one-third of which
C. one-third of whom
D. one-third in which
答案:
A. one-third of them
B. one-third of which
(答案→)C. one-third of whom
D. one-third in which
解析:考查定从。先行词是students指人,所以关系代词要用whom;选C。