- https://matchthememory.com/irregularverbs
- 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
- https://agendaweb.org/exercises/verbs/simple-past-irregular-4
- https://agendaweb.org/exercises/verbs/irregular-past-4.htm
- http://www.engelsgemist.nl/past-simple-1/
- http://elovivo.com/introenglish/en/intro_english/lessons_wordlist/basic_english_lesson_12/lesson12a_ex.html
- https://www.gamestolearnenglish.com/past-tense-game/
- https://www.esolcourses.com/content/exercises/wordmatch/6/wordmatch.html
- https://www.proprofs.com/quiz-school/quizshow.php?title=irregular-verbs-1-to-20-multiple-choice&q=1
- https://www.quia.com/cb/8111.html?AP_rand=1227307875
- https://www.quia.com/cb/8111.html
- https://www.quia.com/pop/136855.html?AP_rand=154488035
- http://www.focus.olsztyn.pl/en-the-past-simple-tense-exercises.html#.XJs2mKSCHIU
- http://www.english-room.com/grammar/pastsimpletense_01.htm
- http://www.english-room.com/grammar/pastsimpletense_02.htm
- http://www.english-room.com/grammar/pasttense_weekend1.htm
- https://www.grammar.cl/Games/Past_Irregular_Verbs.htm
- http://www.learn-english-online.org/Lesson29/TestIt/SimplePast.htm
- https://www.montsemorales.com/gramatica/PastSimpAffIrregSw2-4.htm
- https://www.cambridgeenglish.org/learning-english/activities-for-learners/a1g003-past-simple-of-irregular-verbs
- https://www.esolcourses.com/content/exercises/grammar/pastsimple/page1.html