WAS / WERE

http://www.ego4u.com/en/cram-up/grammar/simple-past/exercises?03

http://suz.digitaleschulebayern.de/english/grammar/was_were1.htm

http://www.englishexercises.org/makeagame/viewgame.asp?id=2009

http://www.englishexercises.org/makeagame/viewgame.asp?id=2023