vs
QUICK ANSWER
"Sí" is a form of "sí", an adverb which is often translated as "yes". "Es necesario" is a phrase which is often translated as "it's necessary". Learn more about the difference between "sí" and "es necesario" below.
sí(
see
)An adverb is a word that describes a verb, an adjective, or other adverbs (e.g., to run quickly, very tired).
a. yes
¿Quieres ir al cine? - Sí, pero primero hay que comer.Do you want to go to the movies? - Yes, but let's eat first.
2. (emphatic)
a. no direct translation
This refers to an idiomatic word or phrase for which there is no word-for-word translation.
Yo sí quiero acompañarlos a Disney.I do want to go with you to Disney World.
Ella no aprobó, pero yo sí.She didn't pass, but I did.
An interjection is a short utterance that expresses emotion, hesitation, or protest (e.g., Wow!).
A masculine noun is used with masculine articles and adjectives (e.g., el hombre guapo, el sol amarillo).
A pronoun is a word that stands in for a noun (e.g., she).
a. himself (third person singular masculine)
Suele jugar ajedrez con sí mismo.He usually plays chess against himself.
b. herself (third person singular feminine)
¡Se envió una carta a sí misma!She sent a letter to herself!
c. itself (third person singular)
El hilo se está enredando en sí.The string is getting tangled up in itself.
e. yourself (second person singular formal)
Solo desea el bien para sí.You only wish good for yourself.
f. yourselves (second person plural formal)
¡Solo tienen que creer en sí mismos!You just have to believe in yourselves!
es necesario(
ehs
neh
-
seh
-
sah
-
ryoh
)A phrase is a group of words commonly used together (e.g., once upon a time).
1. (general)
a. it's necessary
¿Quieres que pase la noche aquí contigo? - No, no es necesario. Vete a casa, papá.Do you want me to spend the night here with you? - No, it's not necessary. Go home, Dad.
b. it's needed
Es necesario un mayor esfuerzo presupuestario para sostener el sistema de salud.A greater budgetary effort is needed to help sustain the health system.
c. no direct translation
This refers to an idiomatic word or phrase for which there is no word-for-word translation.
Es necesario que seamos más tolerantes.We should be more tolerant.
Es necesario pagar impuestos para tener buenos servicios públicos.You need to pay taxes to have good public services.
