听力原文: Workers in New York City have laid the cornerstone for a new building at the site of the destroyed World Trade Center. Sunday's ceremony marked the start of construction on the Freedom Tower, a seventy-story skyscraper that will be topped by a spire meant to suggest the Statue of Liberty. The building's height will be 1,776 feet, a number chosen to evoke America's year of independence. What will the spire on the top of the new building suggest?