OBJECT PRONOUNS

http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-13991.php

http://www.englishexercises.org/makeagame/viewgame.asp?id=1965

http://www.eflnet.com/tutorials/subobjpronouns.php
http://www.englisch-hilfen.de/en/exercises/pronouns/personal_pronouns3.htm
http://www.englishexercises.org/makeagame/viewgame.asp?id=999

In this exercise you have to write complete sentences:

http://www.eflnet.com/grammar/pronouns.php