Proofread the sentences. Which word is spelled incorrectly? In the vestibule below was a letter-box into which no letter would go, and an electric button from which no mortal finger could coax a ring. It was well perhaps that life thus early gave me a hint of one of her most obstenate and insoluble riddles. His arguments are well thought-out and almost irrefutable, and he comes up with them instantaneously. Secret operations of government espionage go back to the beginnings of the United States.