Please go to the following pages and develop the exercises
http://www.englisch-hilfen.de/en/exercises/pronouns/personal_pronouns3.htm
http://www.englishexercises.org/makeagame/viewgame.asp?id=1965
http://www.ego4u.com/en/cram-up/grammar/pronouns/exercises?02
IMPORTANT ASPECTS TO READ ABOUT:
Go to the following links, read the important infromation
http://esl.about.com/od/grammarforbeginners/a/g_cucount.htm
http://englishmistakeswelcome.com/countable_and_uncountable_nouns.htm
http://www.saberingles.com.ar/lists/uncountable.html
To read and develop
http://www.inglestotal.com/countable-and-uncountable-nouns-sustantivos-contables-y-no-contables/
I hope you enjoy!!!!
http://youtu.be/cQnD3qJiJPo
http://youtu.be/3-R1LhVuHfs