They hadn't been waiting for two hours.
Habías estado leyendo desde esta mañana.
Indicates an action that was performed in the past before another ocurred.
Sujeto + had + not + been + v. en forma -ing
Had + sujeto + been + verbo en forma -ing.
Pasado Perfecto Continuo
¿Había estado bailando mucho tiempo?
Past Perfect Continuous
Sujeto + had + been + verbo en forma -ing.
When had you been learning karate?
He had been repairing the car before they went.
Had I been dancing for too long?
Estructura afirmativa
Had + sujeto + not + been + verbo en forma -ing.
We had not been playing football.
Estrucutra interrogativa afirmativa
No habíamos estado jugando al fútbol.
She had been living here.
Había estado viviendo aquí.
Estrucutra interrogativa negativa
Indica una acción que se realizó en el pasado antes de que ocurriera otra.
Estructura negativa
You had been reading since this morning.