The Past Perfect (had + past participle)

The Past Perfect Continuous (had + been + -ing form)

Is used for a past action or event that happened a stated time in the past.

Jim had completed his project by 6 p.m. yesterday.

Is used for a past action that for some time up to a stated time in the past.

Jim had been working for 3 hours by 6 o'clock yesterday.

Is used for a past action or event that happened another past action.

When we arrived at the theatre, the play had already started.

Is used for a past action that for some time before another past action.

When I looked out of the window, I saw that it had been snowing all night.

Is used for a past action that finished in the past and whose were visible in the past.

He was terrified because he had seen a monster.

Is used when we focus on the of the action.

He had been driving for four hours.

Is the past equivalent of the .

He had never travelled by plane.

Is the past equivalent of the .

He had been waiting for a long time.