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"So" is a form of "so", an adverb which is often translated as "tan". "And" is a conjunction which is often translated as "y". Learn more about the difference between "and" and "so" below.
and(
ahnd
)A conjunction is a word that connects words, phrases, clauses, or sentences (e.g., The cat and the dog slept.).
1. (general)
a. y 
I'm going to the beach with my sister and my brother.Voy a la playa con mi hermana y mi hermano.
b. e  (before -i or -hi)
Maria and Isabelle had lunch together last week.María e Isabelle almorzaron juntas la semana pasada.
so(
so
)An adverb is a word that describes a verb, an adjective, or other adverbs (e.g., to run quickly, very tired).
a. así 
To make a paper airplane, take the piece of paper and fold it so.Para hacer un avión de papel, toma la hoja y dóblala así.
b. de esta manera 
Hold the brush so and just dab paint onto the canvas.Aguanta el pincel de esta manera y simplemente pon un poquito de pintura sobre el lienzo.
4. (as stated)
a. así 
Is it possible to insert images into the document? If so, how?¿Es posible introducir imágenes en el documento? Si así es, ¿cómo?
a. y 
But you promised you'd come with me! - So? I changed my mind.¡Pero habías prometido venir conmigo! - ¿Y? Cambié de opinión.
A conjunction is a word that connects words, phrases, clauses, or sentences (e.g., The cat and the dog slept.).
6. (therefore)
a. así que 
We've already finished our work, so we're just going to head home.Ya hemos terminado nuestro trabajo, así que nos vamos a casa.
a. entonces 
So, how long have you been working at the plant?Entonces, ¿cuánto tiempo llevas trabajando en la fábrica?