Question

Cuando usar past perfect and past perfect continuous? , .

Answer 1

"past perfect continuous" se corresponde con el "present perfect continuous" pero se refiere a un tiempo anterior al pasado reciente. Como ocurre con el "present perfect continuous", nos interesa más el proceso que el resultado.
EJEMPLOS

Had you been waiting long before the taxi arrived?
We had been trying to open the door for five minutes when Jane found her key.
It had been raining hard for several hours and the streets were very wet.
Her friends had been thinking of calling the police when she walked in.
Esta construcción se emplea también en el estilo indirecto ("reported speech"). Es el equivalente del "past continuous" y del "present perfect continuous" utilizados en el estilo directo ("direct speech"):

Jane said, "I have been gardening all afternoon." = Jane said she had been gardening all afternoon.
When the police questioned him, John said, "I was working late in the office that night." = When the police questioned him, John told them he had been working late in the office that night.


El pasado perfecto en inglés corresponde al pluscuamperfecto de español. En general, lo usamos para acciones que ocurrieron antes de otra acción en el pasado.
Igual que en el presente perfecto, se forma el pasado perfecto con el verbo auxiliar “to have” y el participio pasado. El verbo auxiliar estará en pasado.