MODALS
http://www.ego4u.com/en/cram-up/grammar/modal-verbs
http://www.englishpage.com/modals/modalintro.html
http://www.perfect-english-grammar.com/modal-verbs.html
http://www.learnenglish.de/grammar/verbmodal.htm
http://www.myenglishpages.com/site_php_files/grammar-lesson-modals.php
http://www.englishclub.com/grammar/verbs-modals.htm
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/certain-probable-or-possible
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/ability-permission-requests-and-advice
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/modals-have
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/can-could-and-could-have
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/may-might-may-have-and-might-have
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/can-or-could
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/will-or-would
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/will-have-or-would-have
http://www.englishpage.com/modals/modalintro.html
http://www.perfect-english-grammar.com/modal-verbs.html
http://www.learnenglish.de/grammar/verbmodal.htm
http://www.myenglishpages.com/site_php_files/grammar-lesson-modals.php
http://www.englishclub.com/grammar/verbs-modals.htm
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/certain-probable-or-possible
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/ability-permission-requests-and-advice
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/modals-have
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/can-could-and-could-have
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/may-might-may-have-and-might-have
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/can-or-could
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/will-or-would
http://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/will-have-or-would-have