to knock someone down with a feather 令人大吃一惊

比喻“you could have knocked me down with a feather 你用一根羽毛就足以打倒我了”可以用来形容什么事情让你大吃一惊，跌破眼镜，难以置信。

例句

You could have knocked me down with a feather when I got the job. I really thought my interview was terrible.

I only entered the competition as a joke. You could have knocked me down with a feather when I won.

请注意

另一个表达 “ruffle someone's feathers 弄乱某人的羽毛”真正的意思是惹火某人或者让某人感觉不自在，不舒服。

例句

The interviewer appeared to ruffle the movie star's feathers when she asked about the lack of success of his recent movies.

I didn't mean to ruffle anyone's feathers I just thought it was better if I did all the speaking in the meeting.