After Sonia's introduction, I clicked on the "Next" button and the conversation screen appeared for about a second (and I can see that the progress bar at the bottom right indicates that I'm 14% complete), but it then faded right into the next portion of the lesson: the discussion of the conversation (where I can see that the progress bar at the bottom right indicates that I'm now 21% complete). I think I missed something. Any ideas on how to solve it?