answer: #Person1# complains to #Person2# that the duty-free shops sell so much liquor. #Person2# explains liquor is considered luxurious and unhealthy so liquor has a higher tax on it, which makes buying liquor duty-free a good deal.
documents: #Person1#: I never understand why these shops have so much liquor.
  #Person2#: What do you mean? It's because it's much cheaper to buy liquor duty-free.
  #Person1#: But why? Why don't people like to buy shirts duty-free? Or shoes? I just don't understand why it's always liquor.
  #Person2#: Well, it's because in most countries liquor has a higher tax on it.
  #Person1#: You mean liquor has a higher tax than other things?
  #Person2#: Yes, of course. Didn't you know that?
  #Person1#: No, I didn't. How high is the tax?
  #Person2#: Well, it is different in different countries. But it's because of the high tax that buying liquor duty-free is such a good deal.
  #Person1#: Why would the government want to tax liquor so much?
  #Person2#: Liquor is considered a luxury item. And also, it is considered as something that isn't very healthy. So if people want to buy it, the government thinks it has the right to tax it.
  #Person1#: That's why a lot of people buy cigarettes here too, isn't it?
  #Person2#: Of course. Cigarettes are also taxed very heavily.