Captain_America_Quotes_Twain.jpg (960×854) & so we sum it up « I don’t understand your point. If you are saying “I am…” cannot be followed by a noun, you are wrong. I am a person. I am the mayor. “Person” and “mayor” are nouns. Although, saying “I am single” would make single an adjective, saying “I am a single” implies that it is a noun.
It isn’t related to the article “a” though, as one could say, “He is president of the club” He- subject, noun, is- linking verb, president- predicate nominative, noun, of- preposition, the- article (diagrammed as describing club), club- noun, and the prepositional phrase “of the club” would be diagrammed as describing president. Big_0ced1ba96acfa7735f06941a5ed09b6801796e29.jpg (1920×1080) My Next Life.