Possession

From The ICAL TEFL wiki

There are several ways to show who owns or possesses something in English.

Apostrophe -s

To show that Erica is the owner, we use an apostrophe s added to the owner and make a noun phrase:

Possessive Pronouns

Because Erica is a feminine name, we can use a feminine personal pronoun:

We can also use a possessive pronoun which refers to the whole phrase:

Possessive by Preposition Phrase

With inanimate objects, we normally use of to show possession rather than an apostrophe s:

Compare this with:

We also use of when the possessive noun has a describing clause following it:

We don't use of for adverbs of time:

We can also make possessive noun phrases using prepositions:

Sometimes we can have two types of noun phrase which mean the same thing:

Generally, we use a possessive when the noun is animate, i.e. it is a person or animal, and we use a preposition when the noun is inanimate, i.e. it is a thing. There are a lot of exceptions to this rule, though and many times we can use either pattern.