听力原文： Most Americans think that ice cream is as American as baseball and apple pie. But ice cream was known long before America was discovered. The Roman emperor Nero may have made a kind of ice cream. He hired hundreds of men to bring snow and ice from the mountains. He used it to make cold drinks. Traveler Marco Polo brought back recipes for chilled and frozen milk from China. Hundreds of years later, ice cream reached England. It is said that King Charles I enjoyed that treat very much. There is a story that he bribed his cook to keep the recipe for ice cream a royal secret. Today ice cream is known throughout the world. Americans eat more than two billion quarts a year. (33)