This document provides an overview of modal verbs in English including their meanings and usage patterns. It discusses modal verbs like can, could, may, might, must, should, will, shall, would, ought to, have to/has to, and be able to. It explains that modal verbs are followed by a base verb form and don't take -s in third person present simple. It also notes that modal verbs take "not" for negation and many can't be used in past or future tenses. The document provides examples and substitutes for modal verbs that don't work in all tenses. It concludes with exercises for practicing modal verbs and their substitutes.