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"Besides" is a preposition which is often translated as "además de", and "as well as" is a phrase which is also often translated as "además de". Learn more about the difference between "besides" and "as well as" below.
besides()
A preposition is a word that indicates the relationship between a noun and another word (e.g., He ran through the door.).
1. (apart from)
a. además de
Besides the toiletries, I have to buy a new bathing suit for the trip.Además de los artículos de tocador, tengo que comprar un nuevo traje de baño para el viaje.
as well as()
A phrase is a group of words commonly used together (e.g., once upon a time).
a. tan bien como
I could never play soccer as well as my brother can.Nunca pude jugar al fútbol tan bien como puede mi hermano.