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"Dos" is a form of "dos", an adjective which is often translated as "two". "Tres cosas" is a phrase which is often translated as "three things". Learn more about the difference between "dos" and "tres cosas" below.
dos(
dohs
)An adjective is a word that describes a noun (e.g., the big dog).
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
2. (number)
tres cosas(
trehs
koh
-
sahs
)A phrase is a group of words commonly used together (e.g., once upon a time).
a. three things
Sé que tenía que comprar tres cosas en el supermercado, pero solo recuerdo dos.I know I had to buy three things at the supermarket but I can only recall two.
a. three things
Hay tres cosas que tengo que hacer mañana sin falta antes de ir al aeropuerto.There are three things I have to do tomorrow without fail before going to the airport.