单选题 Mary ______ that piece of cake for twenty yuan.
[A] spent [B] cost [C] bought

【正确答案】 C
【答案解析】[解析] 本题考查近义词辨析。sb. buy sth. 。for some money；sb. spend some money on sth. ；sth. cost sb. some money，注意这三种固定搭配形式。