& 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. Although as far as I know, single is not commonly used in such a context, if we consider possible slang usage, I can understand how it may be used as a noun (similar to “singles.”)