Extra exercises
- https://agendaweb.org/exercises/verbs/past-simple/affirmative-negative-questions-3
- https://www.perfect-english-grammar.com/past-simple-exercise-7.html
- https://agendaweb.org/exercises/verbs/past-simple/affirmative-negative-questions-2
- https://www.montsemorales.com/gramatica/PastSimpAffRegSw2-4.htm