"Do you happen to know
is if she has a boyfriend?"
What does the above sentence means . I heard those line in the movie 'the social network' and I would like to know when do we use this phrase "happen to know" .
Do you happen to know if she has a boyfriend? (I think there's a mistake, it should be if instead of is).
Happen +to infinitive means chance to do something or come about.
Happen to know means do you know by chance?..
Do you happen to know if she has a boyfriend?
It means the same as "Do you know if she has a boyfriend?", with the only difference that the use of happen in front of the to-infinitive "to know" makes the question a polite request.
You can use happen + to-infinitive, including to know, to express that something happens or exists by chance. For examples:
I happen to know his brother.
He happened to have some money.
I never happened to talk to him.
Besides, you can also use happen + to-infinitive to make a polite request. For examples:
Do you happen to know the way to the station?
You don't happen to have any money, do you?
Do you happen to know the time?