单选题 The medicine has many functions, ______are unknown to us.
A. some of that B. some of them C. some of which D. some of what

【正确答案】 C
【答案解析】[解析] 本题考查的是非限定性定语从句中关系代词置于介词之后的语法结构。这是一句复合句,并不是并列句(并列句需要有连词连接)。所以后面一句应是非限定性定语从句,对主句的内容进行补充。非限定性定语从句不能用that作关系词。先行词指代物,只能用which。如果先行词指代人,用some of whom结构。如:I have a lot of students,some of whom are from abroad.