Object pronouns exercises

http://a4esl.org/q/h/9901/jd-pronouns.html
http://www.englishexercises.org/makeagame/viewgame.asp?id=1965
http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-13991.php
http://www.montsemorales.com/gramatica/Objectpronoun.htm
http://www.englishexercises.org/makeagame/viewgame.asp?id=1961
https://www.ego4u.com/en/cram-up/grammar/pronouns/exercises?02