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 was, were

https://agendaweb.org/exercises/verbs/to-be/past-simple-pronouns-forms.html 

https://agendaweb.org/exercises/verbs/to-be-past-simple.htm 

https://agendaweb.org/exercises/verbs/to-be/present-past-forms.htm 

https://agendaweb.org/exercises/verbs/to-be/past-simple-was-were.htm 

https://agendaweb.org/exercises/verbs/to-be/past-simple-negative-forms.html

https://agendaweb.org/exercises/verbs/to-be/past-simple-test-1.html 

https://agendaweb.org/exercises/verbs/to-be/past-simple-questions-1.html 

https://agendaweb.org/exercises/verbs/to-be/past-simple-test-2.html 

https://wordwall.net/resource/29361051/english/was-were 

https://wordwall.net/resource/107430009/past-simple-was-were