ARTICLES

http://www.focus.olsztyn.pl/en-exercises-articles.html

http://www.myenglishpages.com/site_php_files/grammar-exercise-definite-or-zero-article.php

http://www.myenglishpages.com/site_php_files/grammar-exercise-articles.php

http://www.englishexercises.org/makeagame/viewgame.asp?id=6185

http://www.tolearnenglish.com/exercises/exercise-english-1/exercise-english-213.php