Adverbs are words that describe verbs, adjectives, or other adverbs. Examples are provided of adverbs modifying verbs, with "long" describing how much was worked and "swiftly" describing how running was done. The document asks questions about identifying the adverb and modified verb in sample sentences, then provides the answers by identifying "quickly", "all night", and "nervously" as the adverbs and the verbs they modify in each sentence.