Past continuous, past perfect and past perfect continuous

Here are the links for some exercises on past continuous, past perfect and past perfect continuous:

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

http://www.englishpage.com/verbpage/verbs4.htm

http://www.englishpage.com/verbpage/verbs11.htm

http://www.englishpage.com/verbpage/verbs13.htm