1）be good at
意为“擅长……”，后接名词、代词或ving形式。例如：
I’m good at playing chess.
我擅长下象棋。
2）be good with意为“灵巧的；与……相处得好”。
例如：
She is good with her hands.
她手很巧。
He is very good with the children.
他与这些孩子处得很好。
3）be good to意为“对……友好”。
例如：
My friend was good to me when I was ill.
我生病时我的朋友对我关怀备至。
4）be good for意为 “对……有好处”。例如：
Eating more vegetables is good for your health.
多吃蔬菜对你的健康有好处。