I have finished a large part of the book, the rest of which ______ more difficult to me.
【正确答案】 A
【答案解析】本题考查定语从句关系代词的使用。关系代词which在此引导非限定性定语从句,修饰先行词the book。the rest of book视为单数形式,当它作主语时,谓语动词用单数形式,因此排除选项B和D;该句时态属于现在时态中的一种,所以,选项C也被排除。只有A正确。