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"Of" is a preposition which is often translated as "de", and "an" is an indefinite article which is often translated as "un". Learn more about the difference between "of" and "an" below.
of()
A preposition is a word that indicates the relationship between a noun and another word (e.g., He ran through the door.).
an()
An indefinite article is a word that indicates that a noun is not specific (e.g., a girl).
1. (general)
A preposition is a word that indicates the relationship between a noun and another word (e.g., He ran through the door.).