whenever每当 = any time = every time= each time
whenever 无论何时, 引导
让步状语从句,这时候=no matter when
比如:Whenever I saw the picture, I would think of my mother.
每当我看到这张照片时, 我会想起母亲。 这里whenever= any time= every time= each time
You can stay at my cottage in the country whenever you like.
只要你愿意,无论什么时候都可以住在我乡下的小屋里。这里whenver = no matter when