1. Past Perfect (had + past participle) = I had worked
2. Past Perfect Continuous (had been + -ing verb) = I had been working
🔹 Usamos el past perfect simple con verbos de acción para enfatizar la finalización de un evento.
She had finished her homework before dinner. (Ella ya había terminado los deberes antes de la cena).
By the time we arrived, the film had started. (Cuando llegamos, la película ya había empezado).
🔹 Usamos el past perfect continuous para mostrar que un evento o acción en el pasado seguía en curso o desarrollándose, enfatizando la duración de la actividad.
They had been studying for two hours before the exam started. (Llevaban estudiando durante dos horas antes de que empezara el examen).
I was tired because I had been working all day. (Estaba cansado porque había estado trabajando todo el día).
3. Comparación directa
She had read the book before the class. (Había leído el libro → acción terminada, resultado).
She had been reading the book before the class. (Había estado leyendo el libro → acción en proceso, se enfatiza el tiempo invertido).
The builders had put up the scaffolding around the house ➡️ la acción se completó (el andamio ya está colocado).
The builders had been putting up the scaffolding when the roof fell in ➡️ la acción estaba en progreso.
I’d waited an hour for the bus ➡️ la actividad finalizó (la espera terminó).
I’d been waiting an hour for the bus ➡️ se centra en la duración de la espera.
She’d always lived with her parents ➡️ No sabemos durante cuánto tiempo (puede ser permanente).
She’d been living with her parents ➡️ Sugiere una situación temporal.
¡RECUERDA! Hay verbos que normalmente no usamos en forma continua
❌ No usamos la forma continua con:
Verbos de procesos mentales (know, like, understand, believe).
Verbos de los sentidos (hear, smell, taste).
We’d known for a long time that the company was going to close. (Not: We’d been knowing …)
We’d tasted the milk and had decided it was bad, so we threw it away. (Not: We’d been tasting the milk …)
❌ Tampoco usamos la forma continua con acciones puntuales (que suceden de una vez), como start o stop:
Had they started the game on time? (Not: Had they been starting the game on time?)
En inglés hablado, muchas veces se sustituye por el past simple o el past continuous, y el contexto aclara el significado:
👉 My friend had texted me five times before I answered. = My friend texted me five times before I answered.
👉 We had been waiting for two hours before she arrived. = We were waiting for two hours before she arrived.
https://www.perfect-english-grammar.com/past-perfect-past-perfect-continuous-exercise-1.html
Oxford Learner’s — Past Perfect Simple / Continuous: oxfordlearnersdictionaries.com