第一篇 Today's lecture will center on prehistoric people of the Nevada desert. Now, most of these prehistoric desert people moved across the countryside throughout the year. You might think that they were wandering(漫游;徘徊) aimlessly([ˈeɪmləs]) --- far from it! They actually followed a series of carefully planned moves. Where they moved depended on where food was available --- places where plants were ripening([ˈraɪpən]成熟;长成) or fish were spawning([spɔn]产卵). Now often when these people moved, they carried all their possessions([pəˈzeʃ(ə)n] 财产;所有权;占有物,所有物)on their backs, but if the journey was long, extra food and tools were sometimes stored in caves or beneath(在...之下)rocks. One of these caves is now an exciting archaeological site(遗址). Beyond its small opening is a huge underground grotto([ˈɡrɑtoʊ]洞穴). Even though the cave's very large, it was certainly too dark and dusty for the travelers to live in --- but it was a great place to hide things, and tremendous([trəˈmendəs] 可怕的,惊人的)amounts of food supplies and artifacts(人工制品)have been found there. The food includes dried fish, seeds, and nuts. The artifacts include stone spear([spɪr]矛,标枪,鱼叉)points and knives; the spear points are actually rather(稍微,有点;相当,颇;比较地说) small. Here's a picture of some that were found. You can see their size in relation to the hands holding them. 第二篇 Well, if there are no more questions I would like to continue our discussion of human evolution by looking at Homo erectus(直立猿类), the earliest of our ancestors who stood upright. Homo erectus lived about one and a half million years ago and was given that name because, at the time the first fossil was discovered, it represented the first primate（[ˈpraɪmɪt,灵长目动物）to stand upright. There is evidence now that Homo erectus had sharper mental（[ˈment(ə)l] 精神的,智慧的,思想的;心理的）skills than their predecessors（[ˈpredəˈsesər] 前任;前辈;〈古〉祖先）. They constructed the first standardized tool for hunting and butchering([ˈbʊtʃər]n.屠杀者,刽子手;残酷的人v.屠宰;屠杀). They created an extraordinary stone implement([ˈɪmpləmənt]工具;器具), a large teardrop-shaped hand ax([æks]斧)whose design and symmetry([ˈsɪmətri] 对称;匀称;调和;)reveal([rɪˈvil]显露,揭露,揭发,) a keen([kin] 敏锐的,敏捷的,锐利的, ,强烈的,激烈的)sense of aesthetics. This detailing, along with the ax's utilitarian value, strongly suggest that Homo erectus had the ability to conceive ([kənˈsiv] 表达,想出;怀(恨等),抱有(思想),陈述)of and execute([ˈeksəˈkjut]实行,实施,执行) a design to specification(规范,规格). In addition, Homo erectus was the first hominid ([ˈhɑmənɪd]原人,原始人类 [HAH muh nid]) to use fire. This discovery enticed ([ɪnˈtaɪs]引诱,怂恿) them to cook meat, which they could flavor ([ˈfleɪvər]给...增加香气,给...添风味)and keep from spilling([spɪl]引火用纸捻儿,引柴)by flame([fleɪm]火焰;光辉,光芒) and which paleontologists ([ˈpelɪɑnˈtɑlədʒɪst]古生物学者) now believe may have given them a new disease. Some fossil bones of Homo erectus are grossly([ɡroʊs]显著的;严重的;粗劣的,粗糙的;肥大的;魁伟的)deformed, and paleontologists have noted that this condition is similar to that found in people today who have been exposed(使暴露,使曝露)to chronic ([ˈkrɑnɪk]慢性的;长期的;)overdoses {[ˈəʊvə(r)ˈdəʊs] (使)过量用药,(使)服药过量}of vitamin A. Apparently Homo erectus first got this disease by eating large amounts of animal liver(肝脏). 第三篇 I understand your professor has been discussing several Eastern Woodland Indian tribes[traɪb]部落,部族;种族in your study of Native American cultures. As you have probably learned, the Eastern Woodland Indians get their name from the forest-covered areas of the Eastern United States where they lived. The earliest Woodland cultures date back 9,000 years, but the group we'll focus on dates back only to about 700 A.D. We now call these Native Americans the Mississippian 密西西比河的culture, because they settled in the Mississippi River valley. This civilization is known for its flat-topped平顶的monuments[ˈmɑnjəmənt]纪念碑,石碑;墓碑;called temple[ˈtemp(ə)l]庙宇,寺院 mounds小山,筑堤,宝珠;帝位的象征,小丘. They were made The Mississippian people were city dwellers. But some city residents earned their living as farmers, tending the fields of corn, beans, and squash[skwɑʃ]南瓜,倭瓜;荀瓜;西葫芦that surrounded the city. The city's artisans[ˈɑrtɪzən]工匠,手工业工人made arrowheads[ˈæroʊhed]【植】慈菇, leather goods, pottery[ˈpɑtəri] 陶器类, and jewelry. Traders came from far away to exchange raw materials for these items[ˈaɪtəm] 条,条款,项目. In the slides I'm about to show, you will see models of a Mississippian city. 本文来源：https://www.wddqw.com/doc/1ab49fec19e8b8f67c1cb93c.html