英文科普短文

The Internet is a giant network of computers located all over the world that communicate with each other. The Internet is an international collection of computer networks` that all understand a standard system of addresses and commands, connected together through backbone systems. It was started in 1969, when the U.S. Department of Defence established a nationwide network to connect a handful of universities and contractors. The original idea was to increase computing capacity that could be shared by users in many locations and to find out what it would take for computer networks to survive a nuclear war or other disaster by providing multiple path between users. People on the ARPNET (as this nationwide network was originally called) quickly discovered that they could exchange messages and conduct electronic "conferences" with distant colleagues for purposes that had nothing to do with the military industrial complex. If somebody else had something interesting stored on their computer, it was a simple matter to obtain a copy (assuming the owner did not protect it). Over the years, additional networks joined which added access to more and more computers. The first international connections, to Norway and England, were added in 1973. Today thousands of networks and millions of computers are connected to the Internet. It is growing so quickly that nobody can say exactly how many users "On the Net". The Internet is the largest repository of information which can provide very very large network [参考译文] Internet是由位于世界各地相互通信的计算机连接而成的巨大的计算机网络。 Internet是计算机网络的国际性的集合，这些网络都符合具有地址和命令的标准体系，并经骨干网连在一起。Internet始建于1969年，当时美国国防部为连接少数几所大学和协议企业而建立了一个全国性网络。最初的想法是要增加计算机能力并可由许多地点的用户共享，并且通过提供用户间多条路径来找到哪一种计算机网络能够在核战或其他灾难中幸存。ARPNET（这种全国网络最初的名称）上的用户很快就发现他们可以与远距离的同事交换消息，并且进行某种目的的电子“会议”，而这些目的与军事工业企业没有任何关系。如果另外一些人在其计算机中存有有趣的东西，得到其拷贝是很容易的事（假定拥有者没有进行保护）。 几年间，新的网络接入使越来越多的计算机加入进来。在1973年进行了第一次与挪威和英国的国际连接。今天，有成千上万的计算机网络和数百万台计算机与Internet相连。Internet发展如此之快以至于没有人能准确地说出网上有多少用户。 Internet是最大的信息宝库，它可以提供非常巨大的网络资源。这种网络资源可分为网络设备资源和网络信息资源。网络设备资源使我们能够进行远程计算和通信。网络信息资源向我们提供各种各样的信息服务，如科学、教育、商务、历史、法律、艺术和娱乐等等。

现代人的历史可追溯到约20万年前

Human Fossils Dated to 195,000 Years

摘要：

对化石的深入分析使现代人的历史可以追溯到19.5万年以前。

Researchers determined that the specimens are around 195,000 years old.

对化石的深入分析使现代人的历史可以追溯到19.5万年以前。通过对1967年于非洲埃塞俄比亚出土的人类骨骼化石进行新一轮的分析研究，科学家日前确定，这些化石的历史比先前认为的还要早大约6.5万年。这一结论说明，现代人类的化石记录可以追溯到大约20万年以前。

据美联社1月16日报道，科学家们认为，这些化石大约有19.5万年的历史，比人们以前推测的还要早6.5万年。遗传学研究曾推测，智人（即现代人）应起源于大约20万年以前，而这项新的研究结果恰好与遗传学研究结果相一致。

这些智人遗骨化石是于1967年在埃塞俄比亚的奥莫河（omo）四周被发掘出来的。出土的包括一些头骨和躯干骨的化石残片。当时，科学家将这些化石称为现代智人（Homo sapiens）化石，并将其历史暂定为13万年。

日前，美国纽约Stony Brook大学的约翰·弗利格尔和他的同事通过考察化石出土地点，并利用更先进的时间测定仪器分析当地的地质结构和岩石标本，他们发现这些化石应该具有19.5万年的历史。（其中答应有5000 年的误差）

科学家认为，重新修订的时间使“现代人起源于非洲”这一理论更具说服力。日期的提前让这些早期现代人有更充足的时间发展他们的文化属性，使他们从非洲大陆分散到亚欧各地。报道说，在此之前，被认为是最古老的智人遗骨化石是由美国科学家1997年在埃塞俄比亚发现的，该化石的历史约为16万年。

一个多世纪以来，智人的起源是人类进化研究中根本性的重大问题。许多科学家认为，智人与人类更原始的祖先一样，发源于非洲。但也有科学家提出，智人是在世界不同地区分别发展起来的。（王高山）

A new analysis of bones unearthed nearly 40 years ago in Ethiopia has pushed the fossil record of modern humans back to nearly 200,000 years ago perhaps close to the dawn of the species.

Researchers determined that the specimens are around 195,000 years old. Previously, the oldest known fossils of Homo sapiens were Ethiopian skulls dated to about 160,000 years ago.

Genetic studies estimate that Homo sapiens arose about 200,000 years ago, so the new research brings the fossil record more in line with that, said John Fleagle of Stony Brook University in New York, an author of the study.

The fossils were found in 1967 near the Omo River in southwestern Ethiopia. One location yielded Omo I, which includes part of a skull plus skeletal bones. Another site produced Omo II, which has more of a skull but no skeletal bones. Neither specimen has a complete face.

Although Omo II shows more primitive characteristics than Omo I, scientists called both specimens Homo sapiens and assigned a tentative age of 130,000 years.

Now, after visiting the discovery sites, analyzing their geology and testing rock samples with more modern dating techniques, Fleagle and colleagues report in Thursday's issue of the journal Nature that both specimens are 195,000 years old, give or take 5,000 years.

Fleagle said the more primitive traits of Omo II may mean the two specimens came from different but overlapping Homo sapiens populations, or that they just represent natural variation within a single population.

To find the age of the skulls, the researchers determined that volcanic rock lying just below the sediment that contained the fossils was about 196,000 years old. They then found evidence that the fossil-bearing sediment was deposited soon after that time.

Paul Renne, director of the Berkeley Geochronology Center, which specializes in dating rocks, said the researchers made "a reasonably good argument" to support their dating of the fossils.

"It's more likely than not," he said, calling the work "very exciting and important."