英语 英语 日语 日语 韩语 韩语 法语 法语 德语 德语 西班牙语 西班牙语 意大利语 意大利语 阿拉伯语 阿拉伯语 葡萄牙语 葡萄牙语 越南语 越南语 俄语 俄语 芬兰语 芬兰语 泰语 泰语 泰语 丹麦语 泰语 对外汉语

SSS 2009-08-14

时间:2010-05-18 06:14来源:互联网 提供网友:mark@li   字体: [ ]
特别声明:本栏目内容均从网络收集或者网友提供,供仅参考试用,我们无法保证内容完整和正确。如果资料损害了您的权益,请与站长联系,我们将及时删除并致以歉意。
    (单词翻译:双击或拖选)

Early modern humans didn’t just chip away at stones to create their tools. They treated stone with fire in a sophisticated fashion, according to research published August 14th in the journal Science.

About 72,000 years ago, our ancestors along coastal1 South Africa made tools from silcrete, a cement-like layer of soil. The silcrete found at archaeological sites was glossy2 with a fine grain and a reddish color. It didn’t match stones in local outcroppings. Researchers from the University of Cape3 Town couldn’t find big enough pieces to learn more, until a couple of years ago. Then a colleague from Arizona State University remarked that a piece of silcrete reminded him of heat-treated tools in the Southwest.

So the researchers set up a fire pit and buried a silcrete sample at high temperature. The next day, the stone looked like ones used by early humans. It flaked4 easily and provided the basic material for complex tools. Until now, heat treatment was thought to have started in Europe 25,000 years ago. This discovery pushes it back tens of thousands of years into Africa—and suggests that the southern African coast may have been the site of a truly Promethean revolution.

 
 


点击收听单词发音收听单词发音  

1 coastal WWiyh     
adj.海岸的,沿海的,沿岸的
参考例句:
  • The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
  • This country will fortify the coastal areas.该国将加强沿海地区的防御。
2 glossy nfvxx     
adj.平滑的;有光泽的
参考例句:
  • I like these glossy spots.我喜欢这些闪闪发光的花点。
  • She had glossy black hair.她长着乌黑发亮的头发。
3 cape ITEy6     
n.海角,岬;披肩,短披风
参考例句:
  • I long for a trip to the Cape of Good Hope.我渴望到好望角去旅行。
  • She was wearing a cape over her dress.她在外套上披着一件披肩。
4 flaked 62b5ec44058865073ee4b2a3d4d24cb9     
精疲力竭的,失去知觉的,睡去的
参考例句:
  • They can see how its colours have faded and where paint has flaked. 他们能看到颜色消退的情况以及油漆剥落的地方。
  • The river from end to end was flaked with coal fleets. 这条河上从头到尾处处都漂着一队一队的煤船。
本文本内容来源于互联网抓取和网友提交,仅供参考,部分栏目没有内容,如果您有更合适的内容,欢迎点击提交分享给大家。
------分隔线----------------------------
TAG标签:   SSS  glossy
顶一下
(3)
100%
踩一下
(0)
0%
最新评论 查看所有评论
发表评论 查看所有评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
验证码:
听力搜索
推荐频道
论坛新贴