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There are two perfect tenses that English learners need to worry about. Present perfect is one of the four most common tenses and needs to be mastered. Past perfect is much less common but still deserves a passive understanding. There’s no statistical reason to justify the study of future perfect.
First off, the perfect tenses aren’t actually tenses; they show verbal aspect. They transfer the relevance of an event from the time it occurred to either the present (present perfect) or to the time of an event that occurred later but still in the past (past perfect). What complicates this whole system is the usage of these tenses is dependent on the speaker and the emphasis given to various aspects of the events rather than any sort of absolute timeline.
I’ve already eaten breakfast
This tells us that a completed action in the past is relevant now. This sentence is telling the listener that the speaker isn’t hungry and doesn’t want anything to eat at the moment. We don’t use this as part of a typical narration; use past simple to narrate or state facts.
Adverbs such as already, recently, just and yet are often used with present perfect. It is becoming increasingly common to use these with past simple as the adverb marks the same information as present perfect does. Hence:
I already ate breakfast
has the same meaning as example . On the other hand,
I ate breakfast at nine o’clock.
is a mere statement of a fact. We don’t know the relationship of the event to the speaker’s current state.
If we state the time that an event occurred (yesterday, last week, 9:00 am, etc.), we can’t use the present perfect tense. In many cases this means we have to create two sentences.
I’ve already had breakfast. I ate at nine.
I’ve been to Sri Lanka. I went there last year.
Examples  and  show another function of past perfect: marking a general topic in a paragraph with details filled in using past simple.
 I’ve always loved traditional English breakfast. When I was little, my mom taught me how to make it. We made it every Saturday morning…
I hadn’t used chopsticks before I moved to China.
This past action (not having used chopsticks) became relevant when I had to use them for the first time in China.
The choice of past perfect is ultimately one of style and emphasis rather than any sort of absolute timeline that has to be followed.
When I lived in America, I never used chopsticks. The first time I used chopsticks in China was really tough!
You could retell this story many ways and avoid using past perfect. When not using chopsticks is in past simple, it’s just another detail in the narrative. When it’s in past perfect, it’s important to the next event in the story.
Past perfect is relatively rare. Don’t overuse it.