modal verbs

practice on Modal verbs here -

overview in English-Russian

http://usefulenglish.ru/grammar/brief-overview-modal-verbs-and-substitutes

http://www.englishpage.com/modals/interactivemodal1.htm

http://usefulenglish.ru/grammar/modal-verbs-exercise-eight

http://www.e-grammar.org/modal-verbs-can-may-must/

http://theenglishcafe.blogspot.com/2008/02/modal-verbs-exercises.html

http://www.englishexercises.org/buscador/buscar.asp?nivel=any&age=0&tipo=any&contents=modals

http://www.englishpage.com/modals/interactivemodal1.htm

http://www.eoioviedo.org/mariav/modalverbs1.htm

http://www.english-test.net/esl/learn/english/grammar/ei007/esl-test.php

http://perso.wanadoo.es/autoenglish/freeexercises.htm#MODAL

http://www.learn-english-today.com/lessons/lesson_contents/modals-ex.htm

http://www.eoioviedo.org/mariav/modalverbs1.htm

http://www.englishexercises.org/makeagame/viewgame.asp?id=2229