【题目】The book which is ________100 yuan is not worth ________，I think.
A.cost; buying
B.worth; to be bought
C.worth; buying
D.paid; buying

【答案】C
【解析】第一空前是is，cost动词原形不对，paid是过去分词，逻辑主语与动词pay不是被动关系，故也不对，worth介词；第二空考察固定结构be worth doing值得做某事。句意：我认为那本价值100元的书不值得买。根据句意，故选C。