be good at sth./doing sth:擅长于某事/擅长做某事……

be good with sb:善于应 对某人，善于和……相处。

造句:

He is good at singing.他擅长唱歌。

The mother is good with old people.这位母亲善于和老人相处。

I am good at teaching English.You are good at playing basketball.My mother is good at doing housework.我你它他她就是三个人称。