idiom. known to every household
v. understand, know
v. know, understand
phr. I don't know how many stars are in the sky.
phr. He doesn't know the meaning of this joke.
v. announce, publish
phr. everyone knows
phr. This spring morning in bed I'm lying. Not to awake till birds are crying. (from the poem "Spring Morning" written by poet Meng Haoran)
phr. Nobody knows the reason inside (of this matter).