Ellos/Ellas/Ustedes (They/You, formal plural): su (singular), sus (plural)
Examples
Nosotros tenemos nuestras bicicletas. (We have our bicycles.)
Vosotros tenéis vuestras maletas. (You have your suitcases - familiar plural.)
Ustedes tienen sus frutas. (You have your fruits - formal plural.)
Ellos tienen sus casas. (They (masc.) have their houses.)
Ellas tienen sus computadoras. (They (fem.) have their computers.)
Prepositional Forms for Clarification or Emphasis
To avoid ambiguity or add emphasis, possessive adjectives can be accompanied or replaced by prepositional phrases using de.
Forms:
de mí (of me)
de ti (of you, familiar)
de él (of him)
de ella (of her)
de usted (of you, formal)
de nosotros/as (of us)
de vosotros/as (of you, familiar plural)
de ellos/as (of them)
de ustedes (of you, formal plural)
Example of Ambiguity and Clarification
Scenario: Steven can't find the Spanish book, and Alice doesn't have the algebra book.
Teacher's initial answer (potentially confusing): Su libro está en la mochila, y su libro está en mi escritorio. (His/Her/Your book is in the backpack, and his/her/your book is on my desk.)
Clarified answer: El libro de él (de Steven) está en la mochila, y el libro de ella (de Alice) está en mi escritorio. (His (Steven's) book is in the backpack, and her (Alice's) book is on my desk.)
Expressing Possession with "de + noun"
The construction de + noun indicates possession.
Format: definite article + thing possessed + de + possessor.
Example: El libro de Raúl es interesante. (Raúl’s book is interesting.)
Note: Do not use apostrophes to express possession in Spanish.
Contraction of "de + el"
de + el contracts to del.
Example: Es la pluma del profesor Gómez. (It is Professor Gómez's pen.)
Do not combine de and él (him). Example: ¿La pluma es de ella? No, es la pluma de él. (Is the pen hers? No, it's his.)
Oral Link (Enlace)
The oral link or 'enlace' between 'de' and 'el' is reflected in the written merging of the two to form 'del'.