Wecommonly use the verbknowwith a noun phrase, with athat-clause or with awh-clause (e.g.who,where,why):
Do youknowthe music shop just by the market square?(+ object)
Weknowthat this must be a difficult decision for you.(+thatclause)
Do youknowwhere to buy batteries for the watch?(+wh-clause)
We don’t use continuous forms ofknow:
She’s a really good teacher andknowsthe names of over two hundred of her students.
Not: …and is knowing the names of….
We’veknowneach other since we were children.
Not:We’ve been knowing each other…
Know how+ infinitive
We do not commonly useknow+to-infinitive. We useknow how+to-infinitive:
Does heknow how to playclassical guitar music?
Not:Does he know to play…
Know+ object + infinitive
In very formal English, we useknow+ object +to-infinitive:
[extract from a reference for a job]
I have worked with John Davidson for five years andknow him to bereliable and hard-working.
Weather experts have neverknown it to snowas heavily as it has this spring.
Knowwithout an object
To refer to general knowledge, we useknowwithout an object:
A:They’re opening a new terminal at Amsterdam airport.
B:Yes, Iknow. (I know that they are opening a new terminal.)
We useknow+ object to refer to what we know from personal experience:
A:They’re opening a new terminal at Amsterdam airport.
B:Yes, Iknowit. (I know the one you mean. I have been there and seen the airport.)
We also sometimes useknow aboutorknow ofwhen we say what we know from general experience (know ofis more formal):
What do youknow aboutthe origins of the American Civil War?
Not:What do you know the origins…
You know
We useyou knowvery often in speaking as a discourse marker. We use it to check that the people we are speaking to share the same knowledge as us and understand what we are saying:
It’s impossible to find time to go to the gym,you know, every day, isn’t it?
See also:
You know
Discourse markers (so, right, okay)