http://www.saberingles.com.ar/lists/verbs.html
http://www.eslgamesplus.com/irregular-past-tense-esl-grammar-jeopardy-quiz-game/
http://matchthememory.com/pastparticiple
http://www.grammar.cl/Games/Past_Participles.htm
http://www.studyspanish.com/lessons/pastperfect.htm
http://www.ego4u.com/en/cram-up/grammar/past-perfect-simple/exercises
http://www.englisch-hilfen.de/en/exercises/tenses/past_perfect_simple_past.htm
http://www.eslgamesplus.com/present-perfect-vs-past-tenses-rally/