The informal contraction, which should only be used in speaking or dialogue, is spelled how's and means how is, how was, or how does.
Example:
How's your brother? (How is your brother?)
How's he paid the rent? (How has he paid the rent?)
How's this system work? (How does this system work?)
The contraction is spelled shouldn't.
The correct spelling of the contraction is should've.
won't
aren't
The contraction is spelled "doesn't." The past tense is didn't.
The contraction form of who is is who's.Example: Who's at the door?
haven't
you're
I've
They're
contact
QTR.