The course that Beijing University offers normally attracts 30 foreign students per year;

问题补充：

The course that Beijing University offers normally attracts 30 foreign students per year; up to half will be from America.

A. in which

B. for whom

C. with which

D. of whom

答案：

A. in which

B. for whom

C. with which

(答案→)D. of whom

解析：考查从句。Whom指代先行词30 foreign students作为of的宾语。句意：北京大学提供的课程正常每年吸引30个外国学生，其中的高达一半来自美国。