answer: Tom and Sam had roast beef and potatoes for lunch and those are exactly what Karen prepares for their dinner.
documents: #Person1#: Hi, Karen! Where's Tom? 
  #Person2#: He's upstairs. He's having a bath. Tom! 
  #Person3#: Yes? 
  #Person2#: Sam's here. 
  #Person3#: I'm nearly ready. Hello, Sam. Have a cigarette. 
  #Person1#: No thanks, Tom. 
  #Person3#: Have a glass of whisky then. 
  #Person1#: OK. Thanks. 
  #Person3#: Is dinner ready, Karen? 
  #Person2#: It's nearly ready. We can have dinner at seven o'clock. 
  #Person3#: Sam and I had lunch together today. We went to a restaurant. 
  #Person2#: What did you have? 
  #Person3#: We had roast beef and potatoes. 
  #Person2#: Oh! 
  #Person3#: What's the matter, Karen? 
  #Person2#: Well, you're going to have roast beef and potatoes again tonight!