新概念二中 one of 用法,新概念二28课的第一句话：Jasper White is one of those people who believes in ancient myths.这里不是one of+复数名词+定语从句吗?定语从句修饰前面的复数名词,为什么从句的动词believe

Question

新概念二中 one of 用法,
新概念二28课的第一句话：Jasper White is one of those people who believes in ancient myths.
这里不是one of+复数名词+定语从句吗?定语从句修饰前面的复数名词,为什么从句的动词believe用的是单数形式?
下面是网友给的用法：
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.
He is one of the boys who enjoy playing basketball.定语从句修饰the boys。
这句话不是和课文中的第一句话，句式一样的吗？

Answer 1

课本错了!
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.