know

To have information about something in your mind.

• I know your name.
• She knew the answer immediately.
• Do you know what time it is?

How to use it: know about something (Do you know about the new rules?); know + question word + clause (I know where she lives.)

Similar words: be aware of

Common phrases: know the answer, know someone's name, know about something, know a secret

To be familiar with a person or place because you have met them or been there.

• Do you know my sister?
• I've known him for years.
• She knows this city very well.

Similar words: be familiar with, be acquainted with

Common phrases: know someone well, know the area, get to know someone

To be sure that something is true.

• I know you're right.
• He knew the plan would work.
• How do you know she's safe?

How to use it: know that + clause (I know that she is telling the truth.)

Similar words: be certain, be sure

Opposites: doubt

Common phrases: know for sure, know for certain, know something is true

To understand a subject or be able to do something through learning or experience.

• I know how to cook.
• He knows several languages.
• Do you know how this machine works?

How to use it: know how to do something (She knows how to repair bicycles.)

Similar words: understand, have mastered

Common phrases: know how to swim, know your subject, know the rules, know your business

A word added at the end of a sentence to remind someone to pay attention to what you said.

• Be careful, know.
• You'll need your ticket, know.
• Don't leave the door open, know.

Similar words: you know

Common phrases: be careful know, it's important know