si no estudias

if you don't study

→ si
phrase Rare #37,625
if you don't study Used to express a condition or warning. The form changes depending on who is being addressed: si no estudias means “if you don't study” to one person, while si no estudian means “if you don't study” or “if you don't study” addressed to multiple people or formally to one person.
SP: Si no estudias para el examen, no vas a aprobarlo.
EN: If you don't study for the exam, you aren't going to pass it.

Si no estudias, no vas a aprobar el examen.

If you don't study, you won't pass the exam.

Está claro que te van a suspender si no estudias más.

It’s clear that you’re going to fail if you don’t study more.

Si no estudias duro, continuarás teniendo bajas calificaciones.

If you don't study hard, you'll continue to get low grades.

Si no estudias y ganas, ¿cómo se casara ella?

If you don't study and earn money, how will she get married?

— 3 Idiots (2009)

Vas a fracasar si no estudias más.

You’re going to fail if you don’t study more.

Si no estudias vas a reprobar el examen.

If you don't study, you're going to fail the exam.