1. ANTE TODO
Possessive adjectives, like descriptive adjectives, are words that are used to qualify people, places, or things.
Possessive adjectives express the quality of ownership or possession.

2. Forms of possessive adjectives
SINGULAR FORMS PLURAL FORMS
mi mis my
tu tus your (fam.)
su sus his, her, its, your (form.)
nuestro/a nuestros/as our
vuestro/a vuestros/as your (fam.)
su sus their, your (form.)

3. COMPARE & CONTRAST
In English, possessive adjectives are invariable; that is, they do not agree in gender and number with the nouns they modify.
my cousin my cousins my aunt my aunts
Spanish possessive adjectives, however, do agree in number with the nouns they modify.
mi primo mis primos mi tía mis tías
The forms nuestro and vuestro agree in both gender and number with the nouns they modify.
nuestro primo nuestra tía
nuestros primos nuestras tías

4. Possessive adjectives are always placed before the nouns they modify.
—¿Está tu novia aquí?
Is your girlfriend here?
—No, mi novia está en la biblioteca.
No, my girlfriend is in the library.

5. los parientes de él/ella his/her relatives
Because su and sus have multiple meanings (your, his, her, their, its), you can avoid confusion by using this construction instead:
[article] + [noun] + de + [subject pronoun].
los parientes de él/ella his/her relatives
sus parientes  los parientes de Ud./Uds. your relatives
los parientes de ellos/ellas their relatives

6. 1. Decide on meaning first, based on the owner. 2
1. Decide on meaning first, based on the owner Then choose the correct form based on the possession or the relationship) i.e. I live in their house. their = su or sus Yo vivo en ____ casa. The possession “casa” is singular, so you pick: su

7. They are my cousins. Ellos son _____primos
They are my cousins. Ellos son _____primos. my = mi or mis The relationship “primos” is plural, so you pick: mis

8. ¡INTÉNTALO! Provide the appropriate form of each possessive adjective.
1. Es ___ (my) libro.
2. ___ (My) familia es ecuatoriana.
3. ___ (Your; fam.) esposo es italiano.
4. ___ (Our) profesor es español.
5. Es ___ (her) reloj.
6. Es ___ (your; fam.) mochila.
7. Es ___ (your; form.) maleta.
8. ___ (their) sobrina es alemana.
___ (her) primos son franceses.
2. ___ (Our) primos son canadienses.
3. Son ___ (their) lápices.
4. ___ (Their) nietos son japoneses.
5. Son ___ (our) plumas.
6. Es ___ (your; fam.) mochila.
7. ___ (my) amigas son inglesas.
8. Son ___ (his) cuadernos.