Many, many years ago, when New York City was in financial difficulty, when the winter was particularly cold, public schools would suddenly declare a holiday for a week, known as a “gas-saving holiday.” The real purpose was to lower the school heating temperature that week and save money. A lot of money to buy diesel. 　　There was a fifteen or sixteen-year-old boy who came home and told his father that he was on holiday to save fuel. 　　”With one week’s leave, plus the Saturdays and Sundays before and after, there are nine days’ leave in total. Do you have any plans?” the boy’s father asked. 　　”I knew you would ask…