A known quantity
Someone or something that is known and understood.The new employee is a known quantity in our office because he worked here before.
A known fact
Something that is generally recognized as a fact.It is a known fact that more people get colds in the winter than in the summer.
Know which side one`s bread is buttered on
To know who can help you and therefore try to please him or her, to know what is good for oneself.The man is careful not to make his boss angry.... Read more →
Know which is which
To be able to distinguish one thing or person from another.The two dogs look the same and I do not know which is which.
Know where (someone) stands on (something)
To know what someone thinks or feels about someone or something.I do not know where the mayor stands on the issue of the new parking fees.
Know when one is not wanted
To sense when one's presence is not welcome.I know when I am not wanted so I will not go to the restaurant.
Know what’s what
To know the facts about something.It is difficult to know what's what with the man's problem.
Know the score
To know the facts (about life or something).The man does not know the score about what is happening at his company.
Know the ropes
To know the procedures in a company, to know how to do something.I know the ropes at my job and I do very well at work.
(not) know the first thing about something
To lack basic knowledge about something.The man does not know the first thing about computers.