GRAMMAR

PAST PERFECT SIMPLE 

Affirmative:                                                     

I / you had finished                                                                  

he/ she/ it  had finished                                                      

we/ you /they had finished        
                                        

Negative:   

I / you had not (hadn't) finished
he/ she/ it   had not (hadn't) finished
we/ you /they  had not (hadn't) finished

Interrogative:

had I /You  finished ?

had he/ she/ it  finished?
had we/ you/ they  finished?

Uses: 

•  A completed action which took place before another action in the past
• Used to (solía) : emma, used to dream about becoming a police woman
• Would (solía) : When I was a child, we would often go to the country 
•  Used to in negative or interrogative: Did your mother use to travel a lot when she was young?

Adverbs of frequency / Time expressions 

  already, just, never, until, before, after, by the time

Examples  

The emergency service boat had just arrived
I had been a pilot for ten years.
John hadn't joined a rescue team recently
the plane had already taken off
By the time he left the island, the tornado has already started