knock/nɒk $ nɑːk/

v. repeatedly hit sth with your hand, esp. in order to attract attention

n. the sound of sb hitting sth with their hand

v. [I] 敲；击：[knock at（或on） sth] There's someone knocking at the door. 有人在敲门。

n. [C] 敲击声；敲门声：[knock at（或on） sth] There was a knock at the door. 有敲门声。

knock 撞倒；击倒：The tree was knocked down by a truck. 树被一辆卡车撞倒了。

音组-ock/-ɒk $ -ɑːk/

block; clock; cock; knock; lock; o'clock; rock; shock; sock