While the student was watching the TedTalk video, I straightened up the papers from the previous activity. Ifka then told me that even a quieter rustling of the paper disturbed the student's attention. Then I realized that the student was unable to answer one or two of my questions, which could cause a rustle. It's just a trifle that I can avoid next time. Thanks to that feedback, I changed the preparation of the lesson. I still have the feeling that I have to catch all or most of the planned activities.
Then I realized that the student was unable to answer one or two of my questions, which could cause a rustle.