know(verb)

to be aware of or to have been informed about

He knows everything; I know he is at home because his car is in the drive; He knows all about it; I know of no reason why you cannot go.

know(verb)

to have learned and to remember

He knows a lot of poetry.

know(verb)

to be aware of the identity of; to be friendly with

I know Mrs Smith; – she lives near me.

know(verb)

to (be able to) recognize or identify

You would hardly know her now; – she has become very thin; He knows a good car when he sees one.