When we want to show that something belongs to somebody or something, we usually add an apostrophe + s ('s ) to a singular noun and an apostrophe (' ) to a plural noun, for example:
- the boy's ball (one boy)
- the boys' ball (two or more boys)
Notice that the number of balls does not matter. The structure is influenced by the possessor and not the possessed.
|one ball||more than one ball|
|one boy||the boy's ball||the boy's balls|
|more than one boy||the boys' ball||the boys' balls|
The structure can be used for a whole phrase:
- the man next door's mother (the mother of the man next door)
- the Queen of England's poodles (the poodles of the Queen of England)
- the boyfriend of my sister
- my sister's boyfriend
Proper Nouns (Names)
We very often use possessive 's with names:
- This is Mary's car.
- Where is Ram's telephone?
- Who took Anthony's pen?
- I like Tara's hair.
When a name ends in s , we usually treat it like any other singular noun, and add 's:
- This is Charles's chair.
But it is possible (especially with older, classical names) to just add the apostrophe ':
- Who was Jesus' father?
Some nouns have irregular plural forms without s (man → men). To show possession, we usually add 's to the plural form of these nouns:
|singular noun||plural noun|
|my child's dog||my children's dog|
|the man's work||the men's work|
|the mouse's cage||the mice's cage|
|a person's clothes||people's clothes|
sources : Original Link