This document defines different types of verbs and modals used in the English language. It discusses action verbs, linking verbs, and helping verbs. It also explains how modals like can, may, must, should and other modals are used to express ideas like permission, obligation, and prohibition. Specifically, it provides examples of how each modal is used to grant or deny permission, show strong vs weak obligations, and indicate what is and is not allowed according to rules.