MODALS OF DEDUCTION

http://www.slideshare.net/DavidMainwood/present-and-past-modals-of-deduction

http://learnenglish.britishcouncil.org/en/grammar-exercises/modals-%E2%80%93-deduction-past

http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-83503.php

A SONG BY REM TO PRACTISE "MIGHT HAVE DONE"