Possessive pronouns

The table below shows subject, object and possessive pronouns used in English.

Subject pronouns	Object pronouns	Possesive pronouns
I	my	mine
you	your	yours
he	his	his
she	her	hers
it	it	its
we	our	ours
you	your	yours
they	their	theirs

Example: Betty showed me her identity card and Tom showed me his.
("his" stands for "identity card") Thanks to possessive pronouns we don't have to repeat the noun which is replaced with them.

Tom's car is much faster than ours. - We can use possessive pronouns when we want to contrast two things of the same type.

Is that tea yours or mine?
It was her fault not theirs.

Possessive pronouns in the function of determiners

1. Function
The possessive pronouns are used to make a definite identification: his cat, their house

2. Meaning

The possessive pronouns refer to the possessors and not the things possessed. everything that a male possesses is his thing, everything that a female possesses is her thing, and everything that an animal or a thing possesses is its thing If there is more than one possessor, their is always used.

3. Form

The form of the personal pronouns is the same for the singular and plural thing possessed:
my daughter, my daughters, his pen, his pens

4. Use

The possessive pronouns which function as determiners are used in the following cases:
a. In reference to parts of the body:
Tom has cut his finger. I have wrenched my ankle.

b. In reference to personal belongings:
This is my car
She has just found her lost purse.

Possessive pronouns in the function of nominals

The possessive pronouns can function as nominals.
This dog is Tom's / his.
This car is the Smith's / theirs.

The expressions of mine, which means 'one of my'.
a brother of mine = 'one of my brothers'
a sister of his = 'one of his sisters'