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"Nuestros padres" is a phrase which is often translated as "our parents", and "ayer" is an adverb which is often translated as "yesterday". Learn more about the difference between "nuestros padres" and "ayer" below.
nuestros padres( 
nwehs
-
trohs
pah
-
drehs
)A phrase is a group of words commonly used together (e.g., once upon a time).
a. our parents 
Nuestros padres se conocieron en un tren en Europa.Our parents met on a train in Europe.
ayer(
ah
-
yehr
)An adverb is a word that describes a verb, an adjective, or other adverbs (e.g., to run quickly, very tired).
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
2. (literary) (recent past)
A word or phrase restricted in usage to literature or established writing (e.g., sex, once upon a time).
a. yesteryear  (literary)
A word or phrase restricted in usage to literature or established writing (e.g., sex, once upon a time).
La vida simple del ayer que echamos tanto de menos.The simple life of yesteryear that we miss so much.