Here you have some links to know more about the Past Continuous and to practise some activities on the Past Simple and Past Continuous:
http://www.ego4u.com/en/cram-up/grammar/past-progressive
http://www.isabelperez.com/happy/tenses/past_cont.htm
http://www.ego4u.com/en/cram-up/grammar/simpas-paspro/exercises