Verbs are words that express actions or link subjects to adjectives or nouns. There are tests to identify verbs and determine if they are transitive, intransitive, or linking verbs. Transitive verbs act upon a direct object, while intransitive verbs do not take direct objects. Linking verbs link subjects to adjectives or nouns but do not act on anything. Phrasal verbs are combinations of verbs and other words that have a meaning different from the verb alone.