PAST SIMPLE AND CONTINUOUS

http://www.perfect-english-grammar.com/past-simple-past-continuous-exercise-1.html

https://elt.oup.com/student/project3rdedition/level5/unit1/grammar/exercise1?cc=us&selLanguage=en

http://www.englishpage.com/verbpage/verbs3.htm

http://www.aulafacil.com/cursos/l22536/idiomas/ingles/ingles-repaso-de-gramatica/ejercicios-past-simple-vs-past-continuous

http://www.englisch-hilfen.de/en/exercises/tenses/simple_past_progressive.htm