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"Si no" is a conjunction which is often translated as "unless", and "o" is a conjunction which is often translated as "or". Learn more about the difference between "si no" and "o" below.
si no(
see
noh
)A conjunction is a word that connects words, phrases, clauses, or sentences (e.g., The cat and the dog slept.).
1. (except if)
a. unless
No pueden pasar a la sala de conferencias si no son prensa.You cannot go into the conference room unless you are press.
a. no direct translation
This refers to an idiomatic word or phrase for which there is no word-for-word translation.
Si no cambia de actitud, va a tener muchos problemas en la vida.If he doesn't change his attitude, he's going to have a lot of trouble in life.
Si no fuera por Merche, nunca lo hubiéramos conseguido.If it weren't for Merche, we'd never have managed it.
b. no direct translation
This refers to an idiomatic word or phrase for which there is no word-for-word translation.
Si no nos hubieran ocultado información, podríamos haber hecho algo al respecto.Had they not hid information from us, we could have done something about it.
Hace tiempo que hubiera dejado mi puesto si no fuera por el profundo respeto que siento hacia el Presidente.I would have resigned my post long ago if it weren't for my profound respect for the president.
3. (or)
a. otherwise
Prueba a llamarlo por teléfono; si no, siempre puedes mandarle un email.Try calling him up; otherwise, you can always send him an email.
b. or else
Tendrás que ayudarme en la casa; si no, ya puedes despedirte de un celular nuevo estas Navidades.You'll have to help me with the house chores; or else, you can forget about getting a new cellphone for Christmas.
o, la o(
oh
)A conjunction is a word that connects words, phrases, clauses, or sentences (e.g., The cat and the dog slept.).
a. either...or
Terminarás tu tarea o por las buenas o por las malas.You're going to finish your homework either the easy way or the hard way.
3. (otherwise)
a. or
La residencia del presidente de los Estados Unidos, o Casa Blanca, fue construida en 1790.The residence of the President of the United States, or the White House, was built in 1790.
A feminine noun is almost always used with feminine articles and adjectives (e.g., la mujer bonita, la luna llena).
