"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
121 = eleven times eleven.
132
If, by supplement, you mean the supplementary angle, the answer is 180-121 = 59 degrees.
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.
"es' is not a prefix in Spanish.