I hope this would clear your vision :) http://www.italki.com/entry/480616

http://www.englishpage.com/verbpage/presentperfect.html http://www.englishpage.com/verbpage/pastperfect.html There are also exercises at the bottom of these pages. The "past participle" looks like a past tense for regular verbs, but for irregular verbs it may be quite different: go / have gone, see / have seen, eat / have eaten. In some cases it could look the same: become / have become, quit / have quit, and so on. There's plenty of information which you can look up online. If there's still a specific problem, feel free to ask about that. Good luck.