answer: #Person2# instructs #Person1# how to take and get off the train.
documents: #Person1#: How much is the fare?
  #Person2#: Three yuan.
  #Person1#: Could you tell me how to use it?
  #Person2#: You put it in the slot at the turnstile and then push the turnstile to get into the platform.
  #Person1#: Oh, I see. By the way, how can I get out of the platform after I get off the train?
  #Person2#: That's very easy. The exit is always open.
  #Person1#: Thank you for your help.
  #Person2#: My pleasure.