定语从句中reason后面能用why引导么The reason why I came here was to get your help.这句话是定语从句么?这句话是对的么?

定语从句中reason后面能用why引导么
The reason why I came here was to get your help.这句话是定语从句么?这句话是对的么?

是 .why I came here修饰 the reason