To form the Present & Past Continuous Tenses the verb ESTAR is conjugated in the Present and Imperfect Tenses respectively and used with a Present Participle. We will first address forming the Present Participle.
2.Comer = Comiendo
3.Vivir = Viviendo
-When the –ER and –IR verb stems end in vowels, -YENDO instead of –IENDO is added.
2.Leer = Le-er = Leyendo
3.Oír = O-ír = Oyendo
2.Pedir = Pidiendo 7. Seguir = Siguiendo
3.Preferir = Prefiriendo 8. Sentir = Sintiendo
4.Dormir = Durmiendo 9. Venir = Viniendo
5.Morir = Muriendo
The Present Continuous
The Past Continuous

2.Están almorzando. – They are having lunch
3.Estamos jugando futbol. – We are playing football.
4.¿Qué estás haciendo ahora? – What are you doing now?
5.¿Estás yendo para comer algo ya? – Are you going to eat something right now?
Past Continuous
2.Estabas leyendo cuando yo salí de la casa. – You were reading when I left the house.
3.Él estaba cantando para su novia. – He was singing for his girlfriend.
4.Estaban caminando alrededor de la casa anoche a las nueve. – They were walking around the house at 9 o’clock last night.
5.Yo estaba viendo la televisión esta mañana cuando llamaste. – I was watching the television this morning when you called.i