Ⅰ. be good at / in 意思接近于 do well in. “在（某方面）出色；擅长……”。be good at / in 强调一种笼统情况，而do well in 可表示一种情况，也可指在具体的一次活动中表现出色。
be good at 的反义词组为：be poor (weak) at (in). do well in 的反义词组为：do badly in. 如：
① Mary is good at / in maths. = Mary does well in maths. 玛丽数学很好（指情况）。= 玛丽数学学得很好。
② Tom did well in (不宜用be good at.指具体一次)that English test / sports meeting.汤姆在那次英语考试中（运动会中）考得很好（表现出色）。
③ Wu Dong does badly in his lessons. = Wu Dong is weak / poor / at / in his lessons.吴冬功课不好。
单词：be good at的近义词、反义词、形近词辨析
be good to/be good at/be good for
Be good to me,for the hair went for you.对我好一点吧。因为头发卖掉是为了你呀。
The gold chain was good enough for Jim's watch.这条金链与吉姆的表很相配。
John was good at his job.约翰工作出色。
<辨析>be good to 意为“对......和善”，good 相当于 kind。be good for 意为“有益于......”、“对......有用”。试比较：He is good to her.他对她和善。He is good for her.他有益于她。be good at 意为“在......方面好”、“善于”，后接名词、代词或动名词。如：This cat is good at catching rats.这只猫很会捉老鼠。
与单词：be good at 相关的例句或者名人名言
Be positive and proactive; be good at learning and thinking.
乐观的心态，积极向上，勤学好问，善于思考；
Conduct oneself amicably , be good at communicating with person.
