A、Because he thought he knew the man. B、Because he wanted to have a look at the newspaper. C、Because the man was reading the art

Tom, a reporter friend of ours, passed the large street level windows of the New York Public Library. He noticed that a man on the other side of the window was reading that day’s newspaper. With delight Tom saw that the paper was open to the very page for which he had written a big article.
    The reporter stopped, fixing his eyes on the man. Would the man read deeply into the article? To the bottom of the page? It was one of those rare, unexpected moments of which a writer dreams. The writer’s nose got closer to the glass. The page wasn’t turned: good, the reader was interested. Our friend stayed there a bit longer to learn the answer to the important question:
    Would the reader turn to the page where the story was continued?
    Two minutes passed. Four minutes. Nothing. The man must be a very slow reader indeed. A few moments more and the writer stepped around to look carefully at the reader’s face, at his eyes. That was when he realized the reader had fallen asleep.
Questions 13 to 15 are based on the passage you have just heard.
13. Why did Tom stop to look at the man?
14. What did Tom expect the man to do next?
15. What was the man doing while Tom was looking at his face?