When does the conversation probably take place?

M: Now, can anyone summarize the main idea of the passage? Yes, Jessie, please?
W: I’m sorry．
M: You look pale, Jessie. Are you all right?
W: No, I’m not feeling well. Mr. Brown．
M: What seems to be the problem?
W: I guess I ate something bad at lunch．
M: And you have a stomachache now?
W: Yes, I think so.
M: Can you walk to the school clinic? Or shall I send for the doctor?
W: No, thanks. It doesn’t matter too much. I will go to the doctor after class.
M: Ok. I’ll finish the class in a minute. Then I’ll send you to the clinic.
W: Thank you so much. Mr. Brown．
M: Don’t mention it.