The course normally attracts 20 students per year,of whose up tohalf will be from abroad.

题目

The course normally attracts 20 students per year,of whose up tohalf will be from abroad.
为什么用of whose?
错了，是of whom

答案

那门课程每学年通常会吸引二十名学生选修,他们中有一半是留学生.
whom 指代前一小句的宾语students,所以用宾格.他们中的,所以用of whom.
请及时采纳,多谢!