提高听力同时，你还可以了解到美国历史上的一些重要事件。请感兴趣的你一听为快吧！

<注意>hints: Hohokam;Adenans; Hopewellians; Anasazi;Hopi;Zuni
These early groups are known as Hohokam, Adenans, Hopewellians, and Anasazi. They built villages and grew crops. Their lives were connected to the land. Family and community were important to them. History shows they told stories and shared information mostly by talking, not writing. Some used a form of picture writing called hieroglyphics. Nature was important to their spiritual beliefs. Some groups built big piles of earth in the shapes of snakes, birds, or pyramids. The different groups traded with each other, but they also fought. No one knows why, but these groups disappeared. Other groups, Hopi and Zuni, later came to this land and prospered. By the time the first Europeans arrived, about two million native people lived in what now is the United States.
这些早期的组织被称为Hohokam, Adenans, Hopewellians, 和Anasazi。他们建村庄和种庄稼。他们的生活与土地密切联系。家族和群落对他们来说很重要。历史表明他们大部分讲故事和分享信息来进行交谈，而不是写。一些人用一种图片的形式写这种形式叫象形文字。大自然对他们精神信仰很重要。一些族群以蛇、鸟或者是金字塔的形状建洞穴。不同的族群相互贸易往来，但是他们也会打仗。没有人知道为什么，这些族群消失了。其他的族群，像Hopi和Zuni，之后来到这片土地然后发展。直到第一批欧洲人到达，大约200万原著民居住在现为美国的土地上。