verb

 

have information to have knowledge or information about something in your mind

"How old is she?" "I don't know."

 

be familiar with to be familiar with a person, place, or thing because you have met them, been there, used it, etc before

I've known Tim since primary school.

 

be able to be able to do something

Do you know how to ski?

 

guess correctly to guess something correctly

I knew she'd arrive late.

 

understand to understand and agree with someone

I know what you mean about Pete - I wouldn't trust him at all.