Use of should / shouldn´t

Please review the following links for grammar info about the modal should.      

1. eclecticenglish.com/grammar/Should1A.html
2. englishgrammarsecrets.com/shouldhave/menu.php
3. englishclub.com/grammar/verbs-modal-should.htm

EXERCISES

1. esl-lounge.com/student/grammar/2g18-should-shouldnt-exercise.php
2. http://www.macmillanenglish.com/uploadedFiles/Inspiration/insp2_ws1.pdf
3. englishexercises.org/makeagame/viewgame.asp?id=1734
4. engvid.com/grammar-past-tense-should/