Modals in Past

Modals in past (Perfect modals)

Bibliography: http://www.slideshare.net/torrestorres/modal-verbs-1133347

Bibliography: http://www.slideshare.net/nurgarriga/modal-verbs-9938515

Speculation and deduction in past

Bibliography: http://www.slideshare.net/MargaRenedo/modal-verbs-16552278

Exercises:

http://www.autoenglish.org/modalverbs/pastmodalsdeduction.htm

http://www.esl-lounge.com/student/grammar/4g66-past-modals-exercise.php

http://web2.uvcs.uvic.ca/elc/studyzone/410/grammar/410-modals-of-possibility-and-probability-for-past-situations1.htm

http://www.perfect-english-grammar.com/could-have-should-have-would-have-exercise-1.html

http://www.ecenglish.com/learnenglish/lessons/modals-deduction-past

http://www.english-at-home.com/lessons/grammar-exercise-past-modals/

https://elt.oup.com/student/headway/int/grammar/unit11/hwy_int_unit09_2?cc=us&selLanguage=en

http://www.agendaweb.org/verbs/modals-mixed-4-exercises.html

http://english4all.pro.br/LEpastmodals.htm