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"Desde hace" is a phrase which is often translated as "for", and "atrás" is an adverb which is often translated as "behind". Learn more about the difference between "desde hace" and "atrás" below.
desde hace()
A phrase is a group of words commonly used together (e.g., once upon a time).
atrás()
An adverb is a word that describes a verb, an adjective, or other adverbs (e.g., to run quickly, very tired).
1. (position)
2. (movement)