3.4.3 Grammar Spot - Possessive pronouns

Person   Possessive Adj      Possessive Pronoun
I                    my                               mine     
You               your                             yours
He                 his                               his
She               her                               hers
It                   its                                its
We                our                               ours
You               your                             yours
They              their                             theirs

1. Possessive adjectives are used before a noun.

    This is my car 

2. Possessive pronouns are used instead of nouns. 

    This car is mine

 Whose - Who's 

When we want to know who owns something, we use Whose. 

3. Whose car is this? 

"Whose" has the same pronounciation as "Who's", but a different meaning. "Who's" is the contraction of "Who is"

Who's the man talking to your sister?