text: people=['mom','dad','sister']
  print(people[2].title()+" cannot attend this dinner.")#无法赴约的人
  people[2]='brother'
  print("Dear "+people[0]+", I'd like to invite you to have dinner with me on Friday at my home.")
  print("Dear "+people[1]+", I'd like to invite you to have dinner with me on Friday at my home.")
  print("Dear "+people[2]+", I'd like to invite you to have dinner with me on Friday at my home.")
  