Modal Auxiliary Verbs are a special class of auxiliary verbs. Like other auxiliaries, modals help another verb in the sentence. But this special class of verbs follow a different sentence structure, and have their own set of rules.
Modal Auxiliary Verb Sentence Structure:
Learn more about Modals:
Silly Comparisons Game
Will
Would you rather…?
Would or Used to
Can
Could
Modals in the 1st, 2nd and 3rd Conditional