Modal Verbs

Can - Could - May - Might

Will - Shall - Would | English Modal Verbs (Part 2)

Should - Must - Have to | English Modal Verbs (Part 3)

Could

http://www.englishpage.com/modals/could.html

Should

http://www.englishpage.com/modals/should.html

Would

http://www.englishpage.com/modals/would.html

Explanations and Exercises

http://www.english.marylo.net/modals.php

https://www.off2class.com/teach-modal-verbs/

Slideshare explanation for Modals (Simpsons)

http://www.slideshare.net/concettadalterio/modal-verbs-3933358

Modal Verbs Role Play

http://www.slideshare.net/emptylahh/modal-verbs-presentation-19444325?related=1

Explanations

http://tx.english-ch.com/teacher/jocelyn/others/modal-verbs-polite-request/

http://tx.english-ch.com/teacher/ery/home/modal-verbs-and-their-substitutes/

Activities for the classroom

http://www.teach-this.com/resources/modal-verbs

Chart

http://learningwithjohn.com/grammar/modal-verbs/