第29题: [单项选择]The course normally attracts 30 students per year, ______ up to half will from overseas. A. in which B. for whom C. with which D. of whom 参考答案:D 答案解析:[解析] 考查“介词+关系代词”引导非限定性定语从句。在本题中,先行名词是students,因此选项A、C可排除。根据题意,空格处应表示“其中”之意,故用 “of+whom”结构。