one of结构作主语,一般情况下,谓语动词都是用单数。但是如果这个结构用作定语从句的先行词,从句谓语动词用复数。但如果前有the only、the very等修饰时,谓语动词用单数。

复数的情况

(1)He is one of the students who were praised at the meeting.
他是在会上被表扬的学生之一。

单数的情况

(1)He is the only one of the students who was praised at the meeting.
他是在会上唯一被表扬的学生。
(2)One of them is from America .
其中一个来自美国。
(3)One of the bags was lost en route.
其中一个包在途中丢失了。
(4)One of the reporters cannoned into Arnold
一个记者和阿诺德撞了个满怀。