(1)be good at 意思是在某方面比较擅长,at指在某一点上。

例句:She is good at dancing and singing.(她在跳舞和唱歌方面比较擅长。)

My younger brother is very good at math.(我的弟弟在数学方面非常擅长。)

(2)be good for意思是对某方面有好处,for指对于什么。

例句:Eating vegetables is good for your health.(吃蔬菜对你的健康有好处。)

Being honest is good for your marriage.(保持诚实对你的婚姻有益处。)

(3)be good to意思是对某人的态度友善,to指对某个人。

例句:You should be good to your mother.(你应该对你的妈妈友善。)

He was not good to his wife before.(他过去对他的妻子不友善。)

(4)be good with意思是擅长和谁相处或打交道,with指和谁。

例句:Tom is good with the children.(Tom善于和这些孩子们打交道。)

I am not good with my boss.(我和我的老板相处的不好。)