Le pronom "en"

Voici la théorie:
http://instruction2.mtsac.edu/french/french2/questionsreponses/en.htm

Exercices:

http://uregina.ca/~laninstit/HotPot/French/Elementaire/exercises/P/p004.htm
http://uregina.ca/~laninstit/HotPot/French/Elementaire/exercises/P/p005.htm