Forms 5ac. Past Simple (had, was/were, could, regular verbs)

For practicing:
The forms of have (have, has, had)
https://agendaweb.org/exercises/verbs/have-has-had.htm;
https://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-4262.php;
https://www.englisch-hilfen.de/en/exercises/tenses/have.htm;
Was/were
https://www.ego4u.com/en/cram-up/grammar/simple-past/exercises?03;
https://www.english-4u.de/en/tenses-exercises/was-were.htm;
https://www.englisch-hilfen.de/en/exercises/tenses/was_were.htm;
Could
https://agendaweb.org/exercises/verbs/modals/can-could-1;
https://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-91443.php;
https://www.perfect-english-grammar.com/modal-verbs-of-ability-exercise-1.html;
Regular verbs
https://agendaweb.org/exercises/verbs/past-simple/regular-forms;
https://www.englisch-hilfen.de/en/exercises/tenses/simple_past_statements.htm;
https://www.grammarbank.com/simple-past-tense-regular-exercise.html;
https://www.english-4u.de/en/tenses-exercises/past-simple2.htm.