answer: #Person2# explains to #Person1# what the tariff is and why government levies the tariff.
documents: #Person1#: Professor wang can I ask a few questions?
  #Person2#: Certainly.
  #Person1#: What is the tariff?
  #Person2#: It's a tax levy by the goveroverment on goods imported into that country.
  #Person1#: Why does the government levy the tariff?
  #Person2#: Tariff provides the government with extra tax revenue.
  #Person1#: Anything else.
  #Person2#: Tariff raises the price at which the goods are sold in the importing country and therefore makes them less competitive with locally produced goods.
  #Person1#: Oh, I know. Thank you. Professor wang.
  #Person2#: Do not mention it.