Here's how it works:
* Present perfect: "have" or "has" + past participle (e.g., "I have eaten breakfast.")
* Past perfect: "had" + past participle (e.g., "He had finished his work before the meeting.")
* Future perfect: "will have" + past participle (e.g., "We will have arrived by tomorrow morning.")
Examples:
* Present perfect: I have written a letter.
* Past perfect: She had studied for hours before the test.
* Future perfect: They will have completed the project by next week.
The perfect tenses emphasize that an action or state was completed at some point in the past, present, or future, and that the result of that action or state continues to be relevant.