Passive Voice Quizzes

http://a4esl.org/q/h/vm/active-passive.html
http://www.eslgo.com/quizzes/raiderspassive.html
http://www.englishclub.com/grammar/verbs-voice_quiz.htm
http://www.better-english.com/grammar/passive1.htm
http://www.autoenglish.org/gr.pas.i.htm