http://www.montsemorales.com/gramatica/tobe1.htm
http://www.members.iinet.net.au/~adelegc/grammar/present_simple/to_be.html
http://www.kico4u.de/english/uebungen/5klasse/findbe.htm
http://www.englishmaven.org/HP6/To_Be_Exercise2.htm
Rodrigo Luquez » Ver perfil