The difference is that now we conjugate Haber in the Imperfect past tense.
The Present Perfect sentence Yo he leído el libro , now becomes the Past Perfect Yo había leído el libro .
The time difference between the Present Perfect and the Past Perfect tense is when they occur on a time line.
For example, using the Present Perfect I can say "I have eaten." You know that the eating on my part is over. I have finished. But it has happened recently.
If I ate my dinner three days ago, I would be unlikely to say "I have eaten." I am more likely to use the Preterite form of "To Eat" to say "I ate dinner three days ago."
However, if I want to say that I had eaten my dinner already when the pizza arrived, I will use the Past Perfect (which I did.)
When we construct a sentence in
the Past Perfect, it generally establishes an event before a more recent event.
If I said, "I had eaten," you can feel that I need to complete the sentence:
"I had eaten when...(or before... or by then.)"
- I had eaten all the roasted garlic by the time Keanu arrived.
- I had groomed my horse thoroughly before I went riding.
- I had finished my shower when the doorbell rang.
Imagine the line below as a timeline:
|+ Preterite||+past perfect||+present perfect||+present||+future|
+++++ I + M + P + E + R + F + E + C + T ++++++++++
The Imperfect is an indefinite period in the Past, the Preterite handles completed time-specific events, and the Present Perfect is for recently completed events. The Past Perfect is for events that have occured prior to other past events.