what is modals

Solution-

Modals are special verbs such as can, must, could, would, etc. which are used with principle verbs to express such ideas as a possibility, permission, necessity, obligation, willingness, ability, etc. Modals are never used alone and are always followed by a principal verb. They provide additional information about the principal verb.
Modals have two forms, positive and negative. For Example, the modal ''can'' is positive while ''cannot/ can't'' is a negative form of the modal.