Other links for extra practice

http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/3cond1.htm

http://www.learnenglishfeelgood.com/g-grammar-thirdconditional1.html

http://www.oup.com/elt/global/products/englishfile/intermediate/a_grammar/file07/nef_int_grammar07_a01/

http://www.oup.com/elt/global/products/englishfile/intermediate/a_grammar/file07/nef_int_grammar07_a02/

http://www.englishexercises.org/makeagame/viewgame.asp?id=3623#a