问题补充:
The course normally attracts 20 students per year, up to half will be from overseas.
A. in which
B. of whom
C. of which
D. for whom
答案:
A. in which
(答案→)B. of whom
C. of which
D. for whom
解析:句意:这个课程正常一年吸引20个学生,其中有一半是来自海外。这里使用了定语从句,先行词是20 students,定语从句中是half of the 20 students will be from overseas.所以用of whom引导定语从句,选B。