should and should have, would and would have, could and could have

This link explains the difference between the modal auxiliary verbs should, could and would and how they are used.

http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv195.shtml

Other website about should have with exercises

http://www.englishgrammarsecrets.com/shouldhave/menu.php

Enjoy yourself