you could have knocked me down with a feather成語所屬單字knockyou could have knocked me down with a featheryou could have knocked me down with a feather — 慣用語慣用語1. Used to express great surprise.1.慣用語釋義令我大吃一驚Used to express great surprise.例句When she said she was moving to Japan, you could have knocked me down with a feather.You could have knocked me down with a feather when I won the lottery.