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"Si" is a form of "si", a conjunction which is often translated as "if". "Lo sé" is a phrase which is often translated as "I know". Learn more about the difference between "si" and "lo sé" below.
si(
see
)A conjunction is a word that connects words, phrases, clauses, or sentences (e.g., The cat and the dog slept.).
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
lo sé(
loh
seh
)A phrase is a group of words commonly used together (e.g., once upon a time).
