- Past continuous:
http://www.isabelperez.com/happy/tenses/past_cont.htm
- Past simple or continuous:
http://english.baladre.org/sedaviwebfront/pastsimplecontinuous.htm
http://english.baladre.org/sedaviwebfront/pastsimplecont2.htm
http://www.englishgrammarsecrets.com/pastsimpleorcontinuous/menu.php