When did the conversation take place?

M: You’re going to wear out that typewriter.
W: Oh, hi. What are you doing here at fills time of night?
M: I should ask you that question. Do you have any idea what time it is?
W: About ten or ten-thirty?
M: It’s nearly midnight.
W: Really? I didn’t have any idea it was so late.
M: Don’t you have an early class tomorrow morning?
W: Yes, at seven o’clock. My spare-time class, the students who go to work right after their lesson.
M: Then you ought to go to bed. What are you writing, anyway?
W: An article I hope I can sell.
M: Oh, another of your newspaper Nieces? What’s this one about?
W: Do you remember that trip I took last month?
M: The one up to the Amazon?
W: Well, that’s what I’m writing about—the new highway and the changes it’s made in the Amazon Valley.
M: It should be interesting.
W: It is. I guess that’s why I forgot all about the time.
M: How many articles have you sold now?
W: About a dozen so far.
M: What kind of newspapers buy them?
W: The papers that carry a lot of foreign news. They usually appear in the big Sunday editions where they need a lot of background stories to help fill up the space between the ads.
M: Is there any future in it?
W: I hope so. As a matter of fact, there’s a chance that I may sell this article to a news service.
M: Then your story would be published in several papers, wouldn’t it?
W: That’s the idea. And I might even be able to do other stories on a regular basis.
M: That would be great. But you’d better quit for the night now. Remember your spare-time class students?
W: All right. I’ll stop, just as soon as I finish this paragraph.