提高聽力同時，你還可以了解到美國歷史上的一些重要事件。請感興趣的你一聽為快吧！
The most recent Ice Age was about 35,000 years ago. Much of the world's water was frozen into big sheets of ice. A land bridge - as wide as 1,500 kilometers - joined Asia and North America. By 12,000 years ago, humans lived throughout much of what now are the Americas. The first "Americans" crossed the land bridge from Asia. Historians believe that they lived in what now is Alaska for thousands of years. They moved south into today's mainland United States. They lived by the Pacific Ocean in the northwest, in the mountains and deserts of the southwest, and along the Mississippi River in the midwest.
最近的冰期大約是在35000年前。世界的水大部分都被凍成大片的冰。一個1500千米的大陸橋連接著亞洲和美國的北部。到了12000年前，人類居住在現(xiàn)今為美洲的各個地區(qū)。第一個穿過大陸橋的“美國人”來自亞洲。歷史學家認為他們住在阿拉斯加幾千年了。他們向南遷移到現(xiàn)在美國本土上。他們住在靠近太平洋西北地區(qū)、 山區(qū)和沙漠的西南部，與中西部地區(qū)密西西比河沿岸。