The Direct Object, is the part of the sentence that directly receives the action of the verb. It is used to replace a person, animal or thing in the conversation or in the writing in order to avoid repetition; when they have already been seen in a sentence or external context where the statement occurs.
In this context the <u>Direct Object pronouns</u> are:
1st person singular: Yo <u>me</u><u> </u>
2nd person singular (informal): Tú <u>te</u>
2nd person singular (formal): Usted <u>lo/la </u>
3rd person singular: El/eso <u>lo</u>, Ella/esa <u>la</u>
1st person plural: Nosotros <u>nos </u>
2nd person plural: Ustedes(In latinAmerica) <u>los/las</u>/Vosotros(In Spain) <u>os</u><u> </u>
3rd person plural: Ellos/Ellas <u>los/las </u>
According to the explanation above and the list, we have to identify <u>who directly receives the action of the verb and then replace it for its corresponding direct object pronoun</u>:
1) No tengo la llave de la habitación (I do not have the key to the room)
In this sentence the element that receives the action of the verb tengo (I have) is la llave (the key), which is the <u>3rd person in singular feminine</u> esa (it). Therefore the corresponding direct object pronoun is <u>la</u>:
<h2>No <u>la</u> tengo</h2>(I do not have them)
2) El botones pone el equipaje en el taxi (The bellboy puts the luggage in the taxi)
In this sentence the element that receives the action of the verb pone (he puts) is equipaje (luggage), which is the <u>3rd person in singular masculine</u> eso (it). Therefore the corresponding direct object pronoun is <u>lo</u>:
<h2>El botones <u>lo</u> pone </h2>(The bellboy puts it)
3) Juanita toma fotos en la playa (Juanita takes pictures on the beach)
In this sentence the element that receives the action of the verb toma (she takes) is fotos (pictures), which is the <u>3rd person in plural feminine</u> ellas (they). Therefore the corresponding direct object pronoun is <u>las</u>:
<h2>Juanita <u>las</u> toma</h2>(Juanita takes them)
4) Mi tío compra un boleto para el partido de fútbol (My uncle buys a ticket for the football game)
In this sentence the element that receives the action of the verb compra (he buys) is boleto (ticket), which is the <u>3rd person in singular masculine</u> eso (it). Therefore the corresponding direct object pronoun is <u>lo</u>:
<h2>Mi tío <u>lo</u> compra</h2>(My uncle buys it)
5) Mis hermanas y yo buscamos a nuestros padres (My sisters and I are looking for our parents)
In this sentence the element that receives the action of the verb buscamos (we are looking for) is padres (parents), which is the <u>3rd person in plural masculine</u> ellos (they). Therefore the corresponding direct object pronoun is <u>los</u>:
<h2>Mis hermanas y yo <u>los</u> buscamos</h2>(My sisters and I are looking for them)
6) Inés y Luisa quieren ver los monumentos (Inés and Luisa want to see the monuments)
In this sentence the element that receives the action of the verbs quieren ver (they want to see) is mounmentos (monuments), which is the <u>3rd person in plural masculine</u> ellos (they). Therefore the corresponding direct object pronoun is <u>los</u>:
<h2>Inés y Luisa <u>los</u> quieren ver</h2>(Inés and Luisa want to see them)
7) Estamos explorando el centro de la ciudad (We are exploring the city center)
In this sentence the element that receives the action of the verb explorando (exploring) is centro de la ciudad (city center), which is the <u>3rd person in singular masculine</u> eso (it). Therefore the corresponding direct object pronoun is <u>lo</u>:
<h2><u>Lo</u> estamos explorando </h2>(We are exploring it)
8) Laura está escribiendo unas postales (Laura is writing some postcards)
In this sentence the element that receives the action of the verb escribiendo (writing) is postales (postcards), which is the <u>3rd person in plural feminine</u> ellas (they). Therefore the corresponding direct object pronoun is <u>las</u>:
<h2>Laura<u> las</u> está escribiendo</h2>(Laura is writting them)