这就是医学博士英语考试的阅读理解题源文章，大家快来感受一下！

小白老师说：今天跟大家分享一篇 New Scientist 的文章，供大家参考，感受一下它的难度和风格。New Scientist 是英国发行的世界顶级科技杂志，也是全国医学博士英语统考阅读理解的重要题源。

全国医学博士英语考试的阅读理解文章全部选自英美主流报刊杂志，并且很少做修改与增删。因此，我们必须对英美报刊文章的特点和规律有所了解，才能更好地把握医博英语考试阅读理解的定位与风格。

英美报刊杂志，尤其是英国的，常用 “客观”、“公正” 来体现报道的价值。即所谓的：

“unprejudiced, unopinionated, uninvolved，unbiased”

不偏不倚，不予评论 ，不加参与，不带偏见

因此，一般说来，作者对于文章探讨的主题都会站在比较中立客观的角度去分析。这也解释了为什么很多医博英语考试阅读理解部分一旦问到作者态度的时候，答案大部分都是跟中立客观有关。

此外，大家也要注意时效性。最近这几年考试中会经常遇到一些时髦话题的文章，比如达芬奇机器人诉讼案等等。所以大家平时最好能够经常关心医疗界和科技界时事，积累一些必要的背景知识，这对于考试而言，大有裨益。

好的，下面我们就来阅读一篇 New Scientist 文章。

Stone tools helpd shape human hands

AROUND 1.7 million years ago, our ancestors’ tools went from basic rocks-banged-together to chipped hand axes. The strength and dexterity needed to make and use the latter quickly shaped our hands into what they are today – judging by a fossil that belongs to the oldest known anatomically modern hand.

The 1.7-million-year-old Acheulean hand axes were some of the first stone tools. Over the next million years, these chunky teardrop-shaped rocks became widely used before being replaced by finer, more precise flint tips. But how our ancestors’ hands evolved into a shape that could make such tools is a bit of a mystery.

Before the hand axes appeared, our ancestors had primitive wrists: good for hanging from branches, but too weak to grasp and handle small objects with much force. And no hand bones had been found to fill the gap between 1.7 million years ago and 800,000 years ago – by which time humans had developed the hands we have today. Now, a new fossil is helping bridge that gap.

In 2010, a team led by Fredrick Kyalo Manthi of the National Museums of Kenya discovered an intriguing bone in the north of the country. Carol Ward of the University of Missouri and colleagues identified it as a third metacarpal, the long bone in the palm between the middle finger and the wrist.

Like modern human metacarpals, it has a small lump at its base – the styloid. This projection helps stabilise the wrist when the hand is gripping small objects between the thumb and fingers. Isotope dating revealed the bone to be about 1.4 million years old. It is likely to have belonged to Homo erectus.

Hand bones of early Homo erectus are almost unknown, says Richard Potts of the Smithsonian Institution in Washington, DC." Having such a well-preserved specimen begins to answer questions about hand evolution," he says.

“This is an exciting find,” agrees Mary Marzke of Arizona State University in Tempe. It shows that our ancestors’ handswere already evolving into their modern form 1.4 million years ago. The forceful, repetitive and sustained processes of tool use, such as digging with rocks, would have made stronger hands desirable, says Marzke.

This would have been particularly useful for knocking off flakes to form and sharpen hand axes, says Potts. Once the important wrist features were in place, it became easier for later hominids to make smaller, finer tools.

Because the fossil is younger than the first tools, Ward’s team believe it is the first evidence of anatomy evolving to suit a new technology. As stone tools became more widespread, those who had the wrist structure to use them would have had an evolutionary advantage over their weaker-wristed kin. “The way we look today has been shaped by our behaviour over millions of years,” says Ward. She presented the research at this week’s meeting of the American Association of Physical Anthropologists in Knoxville, Tennessee.

注释：

ancestor 祖先

dexterity 灵巧，敏捷

fossil 化石

chunky 矮胖，粗短

flint 打火石

primitive wrist 原始的手腕

bridge the gap 填补空白

intriguing 有趣的，迷人的

metacarpal 掌骨

Isotope dating 同位素年代鉴定（date 有鉴定年代的意思）

homo erectus 直立人

hominid 人种

anatomy 解剖学

kin 亲戚，同族