- Positive sentences: https://www.ego4u.com/en/cram-up/grammar/past-progressive/exercises?04
- Negative Sentences: https://www.ego4u.com/en/cram-up/grammar/past-progressive/exercises?05
- Questions: https://www.ego4u.com/en/cram-up/grammar/past-progressive/exercises?06
- Was or Were: https://www.ego4u.com/en/cram-up/grammar/past-progressive/exercises?03
- Past Simple vs. Past Continuous: https://www.ego4u.com/en/cram-up/grammar/simpas-paspro
- Past simple vs Past Continuous- using WHEN: http://www.perfect-english-grammar.com/past-simple-past-continuous-exercise-1.html