answer: #Person2# forgot to wind up #Person2#'s watch. Then #Person1# asks #Person2# to turn on the TV and set the watch by it.
documents: #Person1#: What's the time now?
  #Person2#: Sorry, I don't know, there's something wrong with my watch.
  #Person1#: You've simply forgotten to wind it up, have you? When do you usually wind it up?
  #Person2#: In the coming, before going to work.
  #Person1#: You got up so late today. You have, I think. Turn on the TV and set your watch by it.
  #Person2#: OK. I'll turn it on.
  #Person1#: All right. It's just four o'clock.
  #Person2#: Well, I'm setting my watch at four. Thank you.
  #Person1#: You are welcome.