What are Modal Verbs?
They are Auxiliary Verbs that provide additional and specific meaning to the main verb of the sentence. Modal verbs are sometimes referred to as Modal Auxiliary Verbs because they help other verbs.
Ability, doubt, astonishment, permission, polite, request
Permission, supposition, with doubt, if not prohibition
Obligation, firm necessity, logical, conclusion, probability
Wish, desire, will, confidence,in the future
Moral duty, insistent advice, strict recommendation
Unwillingness, forced circumtances
Wish (wish “to like”), polite request, a habit of the past