First of all, here are the answers to the family relationships vocabulary exercise I gave you a few days ago.

1. La mère de ma mère c’est ma grand-mère.

2. Les enfants de mon oncle ce sont mes cousins.

3. La fille de ma mère c’est ma sœur.

4. Le frère de mon père c’est mon oncle.

5. Le père de mon père c’est mon grand-père.

6. Le frère de mon oncle c’est mon père.

7. La sœur de ma mère c’est ma tante.

8. La sœur de ma tante c’est ma mère.

You may have noticed the use of ma, mon, mes in the above sentences.  These are called adjectifs possessifs in French and possessive adjectives in English.  In all of these examples, I have used the first person possessive adjectives; in other words, the French versions of “my”.  Below are some more examples with third person possessive adjectives; in other words, the French versions of “her”, “his” and “their”.

You must make the possessive adjective agree in gender and number with the noun the object belongs to; in other words, depending on whether the noun is singular or plural / masculine or feminine.

Just to be sure you get it, compare these two sentences:

Il avait invité tous ses amis à sa fête. (He invited all of his friends to his party.)
(just one “owner”)
Ils avaient invité tous leurs amis à leur fête. (They invited all of their friends to their party.)
(more than one “owners”)

Careful though as the possessive adjectives ma, ta and sa before words that begin with vowels or a silent h all end in “n” regardless of whether they are masculine or feminine.  Examples: mon adresse, ton amie, son identité.