¿Cuándo van a ir a la playa, hoy o mañana? - No lo sé. Tendrás que preguntarle a ellos.When are they going to the beach, today or tomorrow? - I don't know. You'll have to ask them.
Tienen que decirme cuándo van a ir a la playa, porque seguramente me iré con ustedes.You have to tell me when you're going to the beach, because I'll probably go with you.