To be the cat's whiskers 是一个老式表达，指某人成为了了不起的人物。

例句

Mary thought she was the cat's whiskers in her new coat.

This is a posh school and everybody thinks its students are the cat's whiskers but the teachers know they are not!

请注意

在英语里，人们用 look like something the cat dragged in 这个表达来形容某物很脏或看起来很邋遢。

My friends and I went to Rio last year during the Carnival. After partying all day and all night, we looked like something the cat dragged in.