In traditional grammars and guide books, the term linking verb is used to refer to verbs that describe the subject or link the subject to some complement such as a predicate adjective or predicate noun. This includes copulas such as the English verb be and its various forms, as well as verbs of perception such as look, sound, or taste and some other verbs that describe the subject, such as seem, become, or remain. In addition to predicate adjectives and predicate nouns, English allows for predicate prepositional phrases as well: John is behind the cocktail cabinet.