When does the conversation most probably take place?

W: What are you reading, Paul?
M: Oh, it’s a book about naval engineering.
W: Why are you reading on a Friday evening?
M: Because I’ve got to write an essay this weekend,
W: What are you going to do when you’re qualified?
M: I don’t know. I’d like to get a job abroad, I think. What are you going to do when your year at Weston is over?
W: I’m going to spend a few weeks touring Britain, then I’m going back to Canada, I suppose.
M: What is John going to do?
W: I think he’s going to open a branch of "Pretty Feet" in London.
M: What is he doing in Italy?
W: He’s seeing some designers there. He’s coming back tomorrow. By the way, what are you and Sue doing on Saturday evening?
M: I don’t know yet. Why?
W: Well, I thought we could cook another of our famous suppers and invite john and Sue.
M: Oh, no! Not potato salad again! Sorry, Barbara, but I really have to read this book.