What Had Already Happened
Past Perfect
The past perfect expresses an action that had finished before another action took place in the past. The past perfect is often used to provide reasons for making a decision in the past.
Example:
I had already visited three state parks by the time I began visiting the national parks.
Had you prepared the sauce before you baked the noodles?
The rooms manager hadn't had time to prepare before he made the presentation.
Positive Form:
Subject + had + past participle + (object(s))
The food purveyors had already packaged the meals before we shipped the meals to the restaurants.
Negative Form:
Subject + had + not + past participle + (object(s))
The rooms manager hadn't had time to prepare before he made the presentation.
Question Form:
(Question Word) + have + subject + past participle?
Had you informed the greeters before locking the entrance?