Read this page, then try this practice.

The possessive adjectives (aggettivi possessivi) are adjectives that describe the quality of ownership or relationship: my uncle, your book, our friend, etc. First have a look at the basic forms, then the discussion of how to use them.


Forms

mio tuo suo Suo nostro vostro loro
my your his/her your our your their

Suo (beginning with the capital letter) is used for the formal your  (singular). In the plural, it is not necessary to distinguish between the formal and informal forms.

The adjective suo means either his or her.  If your need to avoid ambiguity concerning the gender of the owner, you may use the alternative forms, di lui or di lei.
Modello: Giulia e Roberto hanno macchine veloci. Preferisco la Ferrari di lei.

Use as Adjectives

When possessives are adjectives, their endings change depending upon the nouns they modify. Possessive adjectives belong to the class of 4-ending adjectives: -o and -a in the singular and -i and -e in the plural. The following chart may be useful.

libro
m sing
macchina
f sing
libri
m pl
macchine
f pl
mio il mio libro la mia macchina i miei libri le mie macchine
tuo il tuo libro la tua macchina i tuoi libri le tue macchine
suo il suo libro la sua macchina i suoi libri le sue macchine
Suo il Suo libro la Sua macchina i Suoi libri le Sue macchine
nostro il nostro libro la nostra macchina i nostri libri le nostre macchine
vostro il vostro libro la vostra macchina i vostri libri le vostre macchine
loro il loro libro la loro macchina i loro libri le loro macchine

As you can see, loro is an exception among the possessive adjectives, in that its ending never changes.

Remember, the gender (or number) of the person who possesses the object does not determine the ending of the possessive adjective.  Rather the gender and number of the object determines the ending.  For example, my car = la mia macchina, regardless of whether or not the first-person speaker is a man or a woman. The possessive adjective ends in an -a in this case, because macchina is feminine.


Use with Articles

Possessive adjectives almost always appear right before the noun (like in English). Unlike in English, however, they are usually used together with the definite articles (the) (e.g. il, la, etc.). You can note the use of these articles in the chart above.

On the other hand, there are some important exceptions to this article rule. Omit the article when you use possessive adjectives with singular family members, except with loro and with family names which express terms of endearment or with those which appear with another adjective after them. Compare the following:

no article
mia madre (no article)
nostro cugino (no article)
vostra zia (no article)

but…

article
il loro padre (include article with loro)
la mia mamma (include article with term of endearment)
la vostra zia italiana (include article with use of extra adjective)
i tuoi genitori (include article with plural family members)

Final Points on Possession

If you are describing possession with nouns rather than adjectives: (E.g. John’s car, my uncle’s house, my friend’s umbrella, etc.), you must show possession with the preposition di. There is no equivalent in Italian of the ‘s used in English.

John’s car = la macchina di John.
(Literally, the car of John.)
my uncle’s house = la casa di mio zio
(Remember to omit the article!)
my friend’s umbrella = l’ombrello del mio amico
(del is a combination or contraction of di + article!)
Whose car is it? = Di chi è la macchina?