dialogue: #Person1#: Could I have my bill, please?
  #Person2#: Certainly, sir.
  #Person1#: I'm afraid there's been a mistake.
  #Person2#: I'm sorry, sir. What seems to be the trouble?
  #Person1#: I believe you have charged me twice for the same thing. Look, the figure of 6. 5 dollar appears here, then again here.
  #Person2#: I'll just go and check it for you, sir.
summary: #Person1# finds a mistake on the bill, and #Person2# will check it.
topic: check the bill