Exercise 1
Listening and revising grammar http://www.bbc.co.uk/worldservice/learningenglish/radio/specials/92_gramchallenge12/index.shtml
Exercise 2
Matching http://www.bbc.co.uk/worldservice/learningenglish/radio/specials/92_gramchallenge12/page2.shtml
Exercise 3
Multiple choice http://www.usingenglish.com/quizzes/46.html
Exercise 4
Gap filling http://www.ego4u.com/en/cram-up/grammar/passive/exercises?text01
Exercise 5
Gap filling http://www.englisch-hilfen.de/en/exercises/active_passive/sentences_gaps.htm
Exercise 6
Read and identify http://www.grammar-quizzes.com/passiveart.html
