answer: #Person2# pays for her gin and tonic. #Person1# tells her they don't take tips in China.
documents: #Person1#: Hello, ma'am. Can I help you?
  #Person2#: Yes, please. I'd like a gin and tonic.
  #Person1#: Sure, ma'am. Here you are.
  #Person2#: Thank you. How much is it?
  #Person1#: 25 yuan.
  #Person2#: Here's 30. Keep the change.
  #Person1#: Thank you very much, ma'am, but we don't take tips in China.