Yo tengo un libro.
English: I have a book.
'Tener' is the verb used to show possession and relationships in Spanish. It is a high-frequency verb at this level.
Use 'tener' to talk about things people own, family members, age, or features.
Yo tengo un libro.
English: I have a book.
Él tiene una hermana.
English: He has a sister.
Ellos no tienen tiempo.
English: They do not have time.
Ella tiene un teléfono nuevo.
English: She has a new phone.