The formation of possessive nouns and possessive adjectives is sometimes confusing to students. The reason for this is that many languages commonly use 'of' for this construction.
The color of his shirt NOT shirt's color
The ball of his dog NOT his dog's ball
In everyday English, however, we generally use possessive nouns and possessive adjectives rather than this 'of' form.
Possessive adjectives are used instead of possessive nouns when the reference is understood. For example:
Tom is a dog lover. He takes his dog Spike everywhere!
In this case, it is clear that 'his' refers to Tom because of the context. Possessive adjectives are always placed in front of the noun they modify. Here is a list of possessive adjectives:
I - my dog
You - your cat
He - his book
She - her car
It - its color (NOT it's!)
We - our dog
You - your house
They - their farm
That's my dog in the picture.
Does you cat like tuna?
He left his book in the car.
That's her car over there.
Its color is purple!
Our dog is like a member of the family.
Your house isn't far, is it?
Their farm produces pumpkins.
Possessive nouns also modify other nouns to indicate possession.
The building's structure
Form the possessive pronoun by placing an apostrophe (') after the noun + s.
Peter -> Peter's motorcycle
building -> building's structure
When nouns end in 's' it can be difficult to know where to place the 's'. For nouns ending in 's', or to use the possessive with regular plurals, place the apostrophe directly after the 's'. Do not add another 's'.
Parents -> parents' concern for their children
Computers -> computers' manufacturer
Notice that this construction can change the meaning from singular to plural.
The cat's favorite food is tuna. (one cat)
The cats' favorite food is tuna. (more than one cat)
Use possessive pronouns to indicate possession when no noun is used. This is the case when the object of possession is understood from the context.
Whose book is that? It's mine. = It's my book.
Is this your pen? No, it's hers. = It's her pen.
In both cases, the possessive pronoun can be substituted for the possessive adjective because the object of possession is understood from the context.
Here is a list of possessive pronouns.
I - mine
You - yours
He - his
She - hers
We - ours
You - yours
They - theirs
Is this your car? - No, that one over there is mine.
Whose lunch is this? - It's yours.
Whose house is it? - It's his.
Do you know who this belongs to? - It's hers.
This isn't her car. It's ours
Whose picture is this? - It's yours.
Who do those books belong to? - They're theirs.
Finally, possessive nouns can also be used in the same manner as possessive pronouns.
Whose cell phone is that? - It's John's.
Who do these computers belong to? - They're our parents'.
Use these resources for more detailed information on individual possessive forms:
Possessive Nouns - For example, John's house, the bicycle's color, etc.
Possessive Adjectives - For example, our neighborhood, his niece, etc.
Possessive Pronouns - For example, that is mine, this is hers, etc.