她游泳很厉害英语怎么说

你可以说: "She is very good at swimming." 或者 "She is an excellent swimmer."
这两句话的意思都是她游泳很厉害。
"Good at" 和 "excellent" 都是形容词，用来修饰名词 "swimming"，表示她擅长游泳。
例句：
She has been swimming competitively since she was a child, and now she is very good at it.
She spends hours in the pool every day, and it shows in her excellent swimming skills.
中文翻译：
她从小就开始参加游泳比赛，现在她游泳很厉害。
她每天都在游泳池里呆上几个小时，这对她的游泳技术有很大的帮助。