Bat 1. Unit 7.Modal & Modal Perfects

http://www.learnenglishlanguagewell.com/2013/more-exercises-modals-b1b2/

http://www.myenglishpages.com/site_php_files/grammar-exercise-modals.php#.U0OXLPl_t9U

http://a4esl.org/q/h/0101/ig-modals.html

http://es.scribd.com/doc/3305639/Modal-Verbs-Exercise-1

http://www.agendaweb.org/verbs/modals-exercises.html