In English grammar, a modal is a verb that combines with another verb to indicate mood or tense. Modal verbs show possibility, intent, ability, or necessity, and they are used alongside the infinitive form of the main verb of a sentence. They are a type of auxiliary verb (helper verb) and are quite common in English. Examples of modal verbs include can, should, and must. Modal verbs are used to express certain hypothetical conditions, such as advisability, capability, or requests. They are used alongside a main verb to inflect its meaning. Modal verbs come before main verbs and never change form. Modal verbs can be used along with auxiliary verbs to refer to possible past, continuous, or future action.