The possessive case
The possessive case indicates possession.
Read the sentence given below.
This is John’s car.
Here the noun John’s is in the possessive case. A noun which shows ownership or possession is said to be in the possessive case.
How the possessive case is formed
When the noun is singular, we make the possessive form by adding ’s to the noun.
When the noun is plural and does not end in -s, the possessive case is formed by adding ’s to the noun.
The People’s Republic
When the plural noun ends in –s, we simply add an apostrophe (’) without –s to form the possessive.
A boys’ school
Singular nouns ending in –s may form the possessive by adding an apostrophe (’) with or without –s.
Thomas’s house OR Thomas’ house
Yeats’s poems OR Yeats’ poems
In compound nouns, ’s is added to the last word.
My sister-in-law’s daughter
The letter –s is omitted and only the apostrophe (’) is added when too many hissing sounds occur in a word.
For conscience’ sake
For goodness’ sake
For Jesus’ sake