Hindsight is always 20/20

I could have done it better or how to use modals in the past. Listen to the lesson:
http://www.youtube.com/watch?v=X2C8bMztpKI
http://www.youtube.com/watch?v=ZGS2nlduH3g

then practice:
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://elt.oup.com/student/naturalenglish/int/a_grammar/unit11/neint_grammar11_exp?cc=pl&selLanguage=pl
http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-53195.php