must can should exercises 3 C / D

Click on the following links and do the exercises:

http://www.tolearnenglish.com/exercises/exercise-english-1/exercise-english-96.php

www.learnenglishfeelgood.com/lefg1_mixedmodals1.html

www.learnenglishfeelgood.com/lefg1_mixedmodals2.html

www.englishgrammarsecrets.com/musthaveto/exercise2.swf

www.englishgrammarsecrets.com/could/exercise1.swf

www.englishgrammarsecrets.com/could/exercise2.swf

www.englishgrammarsecrets.com/musthaveto/exercise1.swf
http://acacia.pntic.mec.es/agip0002/auro/inicio.html