Past Progressive

Past progressive tense is used to tell what was in progress at a time in the past. It also can indicate that an action was in progress when another action occurred in the past: I was taking a shower when the phone rang.

To watch a video that explains the form and when to use this, click here:

http://www.youtube.com/watch?v=4atq1s8u3q8

To practice further, click here:

http://www.englishpage.com/verbpage/pastcontinuous.html

http://www.ego4u.com/en/cram-up/grammar/past-progressive/exercises?04

http://www.perfect-english-grammar.com/grammar-exercises.html