Understanding the Importance of What Type of Speech One Could Use and What One Could Talk About on Shabbos;
fixing a Hat, Dust on a Hat, a Dent in an Aluminum Foil Pan, Plastic Fruit Cup, and Shaking Down a Thermometer;
Hanging up a Child's Swing, Cutting off Part of a Candle to Fit into the Candelabra on Yom Tov, Cutting Part of the Wick...