El pluscuamperfecto en español es el pretérito perfecto del pasado, dicho de otra manera, el pluscuamperfecto en español lo presenta como algo ocurrido antes de otro acontecimiento en el pasado. De los detalles ya hemos hablado en el capítulo 8.5.3. El past perfect continuous tiene la misma función que el past perfect, pero describe una acción duradera. La mejor forma de traducirlo al español en general es con una perífrasis verbal.

Como sucede con todos los tiempos continuos, hay un verbo auxiliar, to have, que se puede y se debe utilizar para la negación.

ejemplos
He had been reading a letter, when the telephone rang. He had not (hadn't) been reading a letter, when the telephone rang.
She had been studying for her exam, when somebody invited her to a party. She had not (hadn't) been studying for her exam, when somebody invited her to a party.
We had been watching TV, before we went to bed. We had not (hadn't) been watching TV, before we went to bed.
They had been building a house. They had not (hadn't) been building a house.
You had been planning a trip, then the accident destroyed your plans You had not (hadn't) been planning a trip, so the accident couldn't destroy your plans.