The genitive case [s'] of.

We use apostrophe to so show possessions.


Exaample:

• That`s Lucy`s car 

Its means that the car belongs to Lucy.

• My father`s garden is really beautiful and the weather is cold.

The basic rule that you need to know is: Add 's to any personal noun unless it is in the form of a plural ending in -s- in which case, just add an apostrophe (`) .


Examples:

• My teacher`s book is very interesting. 
• Beatris`s watch is very nice. 
• Lucy`s ring is new. 

Plural endings. 

• The girls`uniforms are the most fascinating of the town. 
• The wives`kitchens are very clean. 
• The elephan`s legs are very fat.