for表目的,原因,对象
I went out for shopping.我出去买东西的.
I thank you for helping me.谢谢你帮了我.
I do this for you .我做这都是为了你.
of 表所属关系,表性质
The bedroom of the house is small.这个房子的房间很小
It is kind of you.你人真好（人的品质好,人格好）