1. The direct object pronoun directly precedes a conjugated verb.
In a negative sentence, the pronoun comes between the no
(or other negative word) and the conjugated verb.

Me escuchas.

Ellos no nos dicen la verdad.

2. In a sentence with an infinitive or progressive construction,
the direct object pronoun may be attached to the end of either
the infinitive or the present participle or may come before
the conjugated verb.

¿Tienes que lavar la ropa?.
Sí tengo que lavarla.
Sí la tengo que lavar.

¿Sabes hacer el pastel?.
No, no sé hacerlo.
No lo sé hacer.

¿Estás leyendo el libro?.
Sí, estoy leyéndolo.
Sí, lo estoy leyendo.

Note: When adding an object pronoun to the end
of a present participle, place an accent mark over the
next to the last syllable of the present participle
to retain the correct stress.

3. Direct object pronouns follow and are attached to
affirmative commands, but they precede negative commands.

¡Corta el césped!
Córtalo mañana.
No lo cortes hoy.

Note: An accent mark is added to the next to the
last syllable of an affirmative command before an
object pronoun is attached.