He is good at swimming.
来源：日常用语。
例句：He is good at swimming and always wins the swimming competitions.
中文翻译：他擅长游泳，总是赢得游泳比赛。

He excels in swimming.
来源：正式语境。
例句：He excels in swimming and has won many medals in international competitions.
中文翻译：他擅长游泳，在国际比赛中赢得了许多奖牌。

He is an ace swimmer.
来源：俚语。
例句：He is an ace swimmer and can swim faster than anyone else in his team.
中文翻译：他是一位出色的游泳选手，比他队里的任何人都游得快。

He has a knack for swimming.
来源：口语。
例句：He has a knack for swimming and makes it look effortless.
中文翻译：他擅长游泳，看起来不费力。