问题补充:
He is the only one of the students who a winner of schoolarship for three years.
A. is
B. has been
C. are
D. have been
答案:
A. is
(答案→)B. has been
C. are
D. have been
解析:句意:他是唯一的一个赢得三年奖学金的学生。这里who引导的是定语从句,它在从句中作主语,因为先行词被the only修饰,所以从句的谓语动词应该用单数,故排除CD;又因为从句中有时间状语for three years表示他是奖金的获得者从过去一直持续到现在,所以应该用现在完成时,故选B。