听力原文： The Europeans who left their homeland in the 18th and 19th centuries and settled their homes in North America are referred to as early settlers. Early settlers who came from the eastern parts of the present U.S.A. were used to having many trees around, so they found it rather hard to get used to living in a treeless plain like the state of Nebraska. When they first settled down in Nebraska, they needed large quantities of wood for building houses, making fires and doing many other things. Therefore they started many tree-planting plans that went on for years and years. Finally in 1872, a newspaperman named J. Sterling Morton had an idea: Why not have a special day set aside for planting trees. So Arbor Day was born on April 10th, 1872. The state government announced that it would give prizes to individuals and groups that planted the most trees. On that first day, more than 1,000,000 trees were planted in Nebraska. In this way Nebraska has been full of trees and it's green all the year around. (33)