Have a look at these links:
Can
http://www.theyellowpencil.com/gramacan.html
http://www.shertonenglish.com/resources/es/main-verbs/can.php
http://www.real-english.com/reo/15/unit15.html Watch the videos and do the exercises
http://www.esolcourses.com/uk-english/beginners-grammar/using-can/lesson-2/read-and-write.html
