Vídeo com explicação:https://www.youtube.com/watch?v=JGDLHfIIKS0

Link 0: https://learningapps.org/3675075

Link 1: http://www.usingenglish.com/quizzes/407.html

Link 2: http://usefulenglish.ru/grammar/modal-verbs-exercise-five

Link 3: http://www.englishpage.com/modals/interactivemodal4.htm

Link 4: https://learnenglish.britishcouncil.org/en/english-grammar/verbs/modal-verbs/certain-probable-or-possible

Link 5: http://www.perfect-english-grammar.com/modal-verbs-exercises.html

Link 6: http://www.learnenglish-online.com/grammar/modals/possibility.html