He is the only one of the students who a winner of scholarship for three years.A. is　B.

问题补充：

He is the only one of the students who a winner of scholarship for three years.

A. is

B. are

C. have been

D. has been

答案：

A. is

B. are

C. have been

(答案→)D. has been

解析：考查定语从句和主谓一致。定语从句的先行词是the only one，后面的定语从句中用单数，排除BC。再根据for three years可知这里应该使用完成时。句意：他是学生中唯一的一个三年一直是奖学金获得者得人。