estaban esquiando
-they/you were skiing
Imperfecto progresivo para el sujeto ellos/ellas/ustedes del verbo esquiar.

esquiar

Mientras estaban esquiando tuvieron un accidente: cayeron por un barranco.
Whilst they were out skiing they had an accident: they fell down a deep ravine.
¿Tú recogiste el desorden en la cabaña? - Sí, estaban esquiando cuando decidí limpiarla.
Did you pick up the mess in the cabin? - Yes, you were skiing while I decided to clean it.
Palabra del día
el abeto