Linking verbs are verbs that connect the subject of a sentence to a subject complement, which can be a noun, pronoun, or adjective. They do not show action but instead describe a state of being or condition. The most common linking verb is to be, which includes forms like "is," "are," "was," and "were." Other linking verbs include seem, become, and appear. These verbs help provide more information about the subject by linking it to additional details. For example, in the sentence "The sky is blue," the verb "is" links the subject "sky" to the adjective "blue," describing its state.