answer: #Person1# and #Person2# shop gifts for their father.
documents: #Person1#: I want to buy a gift for my father. Will you go with me to choose one for him?
  #Person2#: Sure. Is it your father's birthday?
  #Person1#: Don't you know? Tomorrow is Father's Day.
  #Person2#: Oh! How could I forget such an important holiday?
  #Person1#: You also need to choose a gift for your father, right?
  #Person2#: Yes, let's go.