knock

n C

1. 敲击，碰撞

• He got a knock on the back when he fell. 他摔倒时撞到了背部。

2. 敲击声，敲门声

• a knock at (或on) the door 敲门声

词组take a knock 遭受挫折，打击

• He really took a big knock when he failed in the college entrance examination. 高考落榜对他来说确实是很大的打击。