this is/ these are

http://www.saberingles.com.ar/curso/lesson04/08.html

that, those

http://www.members.iinet.net.au/~adelegc/grammar/this_that/that_those.html

this, these, that, those

http://eolf.univ-fcomte.fr/uploads/ressources/grammar/01_adjectives/01a_this_that_these_those/01.htm

this, these

http://www.bnv-bamberg.de/home/ulrich.koch/flg/englischinteraktiv/this-these2.htm

this, these, that, those

http://eolf.univ-fcomte.fr/uploads/ressources/grammar/01_adjectives/01a_this_that_these_those/02.htm