"Whose car is it?"
The three words mean: Is John/Juan car
This is the car of John or this is John's car.
"Si es, es" is Spanish for "If it is, it is". If you just mean "si es", that means "if it is". If you mean "Sí es" (with an accent on "Sí"), it means "Yes, it is".
"Es" and "son" mean "is" and "are" in Spanish.
Es - Is
"Éste es su auto" = This is his car "Es su coche" = It's his car
quis es means "who are you?"
"Qué es" means "what is". "Quién es" means "who is."
no = no and es means is
Mañana es. = Tomorrow it is.
Es means "it" in English.