one of 后接可数名词复数,表示什么中的一个,动词用单数第三人称.
One of the apples has gone bad.
但是要注意下面的定语从句：
He is one of the boys who enjoy playing basketball.定语从句修饰the boys.
He is the only one of the boys who enjoys playing basketball.one前面有定冠词the的时候,定语从句是修饰one的,所以动词要用单三形式.