The correct answer to this question is that Emerson believes that a sentence can be grammatical in context but ungrammatical in isolation. Thank you for posting your question. I hope this answer helped you. Let me know if you need more help.
His speech was given on August 28, 1963, on it was given at Lincoln Memorial in Washington DC & Martin Luther King Jr Day also known as civil rights day, commemorates the birth of Martin Luther King, Jr.
