They're used to show actions that are already complete. Each tense is created by adding the helping verbs have, has, had, or will have to the past participle.
No, they're not flawless. Nothing is.
As we learned from Nicolas Cage in Moonstruck, the only things that are perfect in this messed up world are snowflakes and stars.
There are three perfect tenses:
- present perfect (the action started in the past, but it's still going)
- past perfect (the action started and finished in the past, but it happened before another action being referred to)
- future perfect (the action, regardless of when it started, will be completed at some point in the future)