Countable and Uncountable nouns

Countable nouns are easy to recognize. They are things that we can count. For example: "pen". We can count pens. We can have one, two, three or more pens.

Uncountable nouns are substances, concepts etc that we can't divide into separate elements. We can't "count" them. For example, we can't count "milk". We can count "bottles of milk" or "litres of milk", but we can't count "milk" itself. 

Execises: 

http://www.englishexercises.org/makeagame/viewgame.asp?id=3246

http://www.myenglishpages.com/site_php_files/grammar-exercise-countable-uncountable-nouns.php#.VBsxxZRdUuE