Exercises (can-can't)

http://www.ecenglish.com/learnenglish/lessons/can-or-cant
http://www.english-grammar-lessons.com/can/exercise1.html
http://www.english-grammar-lessons.com/can/exercise2.html
http://www.english-grammar-lessons.com/can/exercise3.html
http://www.english-grammar-lessons.com/can/exercise4.html