answer: #Person2# often exercises and likes swimming best. #Person1# thinks butterfly stroke is the hardest, and #Person2# agrees.
documents: #Person1#: You're looking very well.
  #Person2#: Thank you. I try to keep in shape.
  #Person1#: Do you often exercise?
  #Person2#: Yes, as long as I can find the time. I like swimming best.
  #Person1#: What style of swimming do you like best?
  #Person2#: I like the back best. I am good at freestyle stroke, but I usually use breast stroke as it keeps me from getting tired.
  #Person1#: I think butterfly stroke is the most difficult style to learn.
  #Person2#: I agree. I'm not good at it, either. Can you swim? How about going for a swim this Saturday?
  #Person1#: Oh, no. I am quite a stone in the water and cannot swim.