1-To express something which occurred in the remote past
I had seen this movie five years ago
2-If two actions occurred in the past
It is necessary to show which action happened first
When he reached the station.the train had already left
3-to emphasize something which occurred in the past
I had worked hard to pass
Positive sentence
subject + had + v3rd form + object
The teacher had scolded the boy
Negative sentence
subject + had +not + v3rd form + object
He had not stolen my book
Interrogative sentence
had + subject + v3rd form + object
Had they finished their homework
