answer: #Person1# checks the bill and finds it's overcharged. #Person2# apologizes for it and has it changed.
documents: #Person1#: Bill, please.
  #Person2#: Please wait a moment. . . here is the bill. Please check it.
  #Person1#: Excuse me, what's this item for?
  #Person2#: For three bottles of Tsingtao beer.
  #Person1#: But we've can canceled one bottle.
  #Person2#: Oh, I'm sorry. Let me go back to the cashier's to have it changed. ( a few minutes later, the waiter returns with the new bill. )
  #Person1#: I'm sorry for the miscalculation. Here's the new bill. Would you mind checking it again?
  #Person2#: That's all right.
  #Person1#: If you're staying at our hotel, you may sign the bill.