A direct object is the direct recipient of the action of a verb.
I invite the boys. Whom do I invite? The boys.
He reads the book. What does he read? The book.
The nouns boys and books are direct objects. They answer the question what? or whom? Verbs that take a direct object are called transitive verbs. Verbs that do not take a direct object (she walks, I sleep) are intransitive.
Direct object pronouns replace direct object nouns.
I invite the boys. I invite them.
He reads the book. He reads it.
In Italian the forms of the direct object pronouns (i pronomi diretti) are as follows:
SINGULAR
PLURAL
mi me
ci us
ti you (informal)
vi you (informal)
La you (formal m. and f.)
Li you (form., m.)
Le you (form., f.)
lo him, it
li them (m. and f.)
la her, it
le them (f.)