All words in the parentheses are adjectives. Unlike English, in Spanish, adjectives must agree in person (first, second or third) and in number (plural or singular) with the nouns they are modifying. In general, adjectives modifying female nouns end with “-a,” and adjectives modifying male nouns have the suffix “-o” or “-e.” Furthermore, when they modify plural nouns they have the “-s” ending. Taking into account these rules, here are the answers to the questions:
1. No encuentro mis cosas porque la habitación está desordenada. (disorderly)
“desordenada” modifies the noun “la habitación” which it's a singular female noun.
2. Los botones están listos para llevar las maletas al tercer piso. (ready)
“listos” modifies “los botones,” a plural male noun.
3. Dicen que Julieta está enamorada Romeo. (in love with)
“enamorada” modifies “Julieta,” a singular female noun.
4. La casa de mi abuela está limpia. (clean)
“limpia” modifies “la casa,” a singular female noun.
5. Los niños están felices porque van a la playa mañana. (happy)
“felices” modifies “los niños,” a plural male noun.
6. 2 + 2 = 5... No, amigo, estás equivocado. (wrong)
“equivocado” modifies “amigo” a singular male noun.
7. Nosotros estamos aburridos. ¡Vamos a jugar al fútbol! (bored)
“aburridos” modifies “Nosotros” a plural male noun.
8. Es el día del examen final. Pablo y Rosa están nerviosos. (nervous)
“nerviosos” modifies “Pablo y Rosa,” a plural noun. In Spanish when a verb or an adjective refers to a female and a male noun, the adjective and the verb agrees with a plural male noun.
9. Ana está cansada; quiere dormir. (tired)
“cansada” modifies “Ana” a singular female noun.
10. 2 + 2 = 4… Sí, Carlitos seguro . (sure)
“seguro” modifies “Carlitos” a singular male noun.