answer: Nancy tells #Person1# she had a special dinner in a restaurant for the blind in London.
documents: #Person1#: So you're back from London, Nancy.
  #Person2#: Yes, I had a special dinner there.
  #Person1#: Oh? How special? Can you tell me about it?
  #Person2#: OK. We had dinner with my old friend Smith. He is an officer in London. When we arrived at the dining hall, all the lights went out. At that time I was a little angry. But then a waiter gave us an explanation, and we laughed.
  #Person1#: Why did the lights go out?
  #Person2#: Because it's a restaurant for the blind.