意思:
vi. 敲打敲击
vt. 敲打敲击批评
n. 敲敲打爆震声I seem to hear someone knocking at the door.
我好像听到有人在敲门。
I'm not knocking them， they are obviously doing too much.
我不是在说他们的坏话，他们显然是做的太过分了。
The knock on the door woke me up.
敲门声把我吵醒了。
There's someone knocking at the door.
有人在敲门。
There was a knock on the door.
有敲门声。
