By the time the police arrived, the thieves had already escaped - Na hora que a polícia chegou, os ladrões já tinham fugido
had + past participle
By the time I arrived, he had already left. I was hungry because I had not eaten all morning.
The past perfect can be used to emphasise that one event happened before another event in the past. This use helps to make the sequence of events clear.
The past perfect can also be used in reported speech and conditional/if statements.
When I arrived at the party at 9pm, Paul had already left. (He left at 7pm) I had just started eating when the phone rang.
|Basic rules + explanation of 'had had' and 'had already'.||SmallAdvantage|
|Clear examples onstruction, negative form, question form and contraction.||perfect-english-grammar.com|
|Some guidance on when to use the past perfect.||perfect-english-grammar.com|
|An explanation and examples (also available as podcast)||BBC Learning|
|Basic explanation and examples.||tofluency.com|