https://agendaweb.org/exercises/verbs/past-simple-regular
https://agendaweb.org/verbs/past-simple-regular/index.html
http://www.adelescorner.org/grammar/past_tense/past_regular.html
https://www.montsemorales.com/gramatica/PastRegPdcCr.htm
https://agendaweb.org/exercises/verbs/simple-past-irregular-1
https://agendaweb.org/exercises/verbs/irregular-past-1.htm
https://agendaweb.org/exercises/verbs/simple-past-irregular-2
https://agendaweb.org/exercises/verbs/irregular-past-2.htm
https://agendaweb.org/exercises/verbs/simple-past-irregular-3
https://agendaweb.org/exercises/verbs/irregular-past-3.htm
http://www.englishexercises.org/makeagame/viewgame.asp?id=2562