Adjetivs posesives

The possessive adjectives in English are "My, your, his, her, our, their". They show to whom things belong or, in other words, possession. They are adjectives whichmodify a noun (or nouns).
In Spanish, all adjectives must agree in number and usually gender. So the possessive adjectives also must agree with the items being owned.
Forexample,
• if I have one book, it is my book: mi libro
• but if I have two books, they are my books: mis libros.
The possessive adjectives match only the items beingpossessed (owned.) They do not reflect how many owners there are or the gender of the owner/s.

Here is a chart of the possessive adjectives:
Yo form : My
mi(singular): mi cuaderno mi mochila
mis (plural): mis cuadernos mis mochilas
Tú form: Your
tu (singular) tu cuaderno tu mochila
tus (plural): tus cuadernos tus mochilasÉl, ella, usted form: His, her, your (polite form)
su (singular): su cuaderno su mochila
sus (plural) sus cuadernos sus mochilas
Ellos, ellas, ustedes form: Their, your(all y'all's)(polite form)
su (singular): su cuaderno su mochila
sus (plural): sus cuadernos sus mochilas
Nosotros form: Our
Since the Nosotros possessive form endsin o, it has four (4) forms like any other adjective ending in o. It must agree in gender as well as number.
masculine feminine
nuestro/a(singular): nuestro cuadernonuestra mochila
nuestros/as(plural): nuestroscuadernos nuestrasmochilas
There is no possessive "S" in Spanish.
When we ask, "Whose book is it?" ¿De quién es ellibro?
We can answer, "It is her book." Es su libro.
If we want to answer, "It is Susana's book", we cannot say *Es Susana's libro.
We must say, Es el libro de Susana.