http://www.englisch-hilfen.de/en/exercises/tenses/simple_past_ed.htm
http://www.englisch-hilfen.de/en/exercises/irregular_verbs/find_regular2.htm
http://www.englisch-hilfen.de/en/exercises/tenses/simple_past_ed2.htm
para imprimir http://www.englisch-hilfen.de/en/exercises/tenses/simple_past_ed2.htm
http://www.englishforeveryone.org/PDFs/irregular%20verbs%20that%20stay%20the%20same%20chart%20-%20%20alphabetical%20order.pdf
http://www.englishpage.com/irregularverbs/interactiveirregularverbs1.htm
