modal verbs

Can/could/be able to: http://www.englishclub.com/grammar/verbs-modals_can.htm http://presentsimpleesl.wordpress.com/2012/10/09/can-vs-be-able-to/ http://suite101.com/article/esl-expressing-ability-with-modal-verbs-can-could-be-able-to-a411551 http://www.engvid.com/expressing-ability-can-could-be-able-to/ (Video lesson) should/ought to/had better: http://web2.uvcs.uvic.ca/courses/elc/studyzone/330/grammar/330-modals-advice.htm http://www.youtube.com/watch?v=00k85ENbak4 (video) http://www.englishpage.com/modals/should.html http://www.englishpage.com/modals/oughtto.html http://www.englishpage.com/modals/hadbetter.html have to/must/don’t have to/ must not http://www.englishpage.com/modals/must.html http://www.englishpage.com/modals/haveto.html http://www.englishpage.com/modals/havegotto.html http://web2.uvcs.uvic.ca/courses/elc/studyzone/330/grammar/330-modals-not.htm be supposed to http://www.learnamericanenglishonline.com/Green%20Level/G7%20Suppossed%20to.html (with video) on present simple/progressive