he is the only one of the student who____a winner of scholarship for three years.

问题描述:

he is the only one of the student who____a winner of scholarship for three years.
a.is b.has been
这里为什么不能是is呢?

he is the only one of the student
who____a winner of scholarship for three years.只看从句.时间已经有三年了,已经是发生了三年的事情,用现在完成时