Verb to be in simple present:
http://www.members.iinet.net.au/~adelegc/grammar/present_simple/to_be_quests.html
http://www.members.iinet.net.au/~adelegc/grammar/present_simple/to_be_neg.html
In the classroom:
http://www.englishexercises.org/makeagame/viewgame.asp?id=360
