单选题 He is the only one of those boys who ______willing to take a make-up exam
A. is B. were C. has been D. was

【正确答案】 A
【答案解析】[解析] 他是愿意参加补考的唯一男生。
[考点] 句法结构
[解析] 本题考核主谓一致的语法现象。主句为一般现在时，而定语从句的先行词是单数概念，所以定语从句的谓语也要用一般现在时单数形式。