Now listen carefully and answer questions 31 to 40.
现在仔细听录音，回答第三十一题至第四十题。
Hello, everyone and welcome. As part of this series of lectures on the development of early humans, today we are looking at rock art: the paintings and drawings produced by prehistoric peoples as they spread across the continents.
大家好，欢迎各位的到来。作为关于早期人类发展系列课程的一部分，今天这节课我们讲的是岩石艺术——史前人类在传遍大陆中创作的绘画作品。
If you've been lucky enough to look at a piece of rock art close up, you'll know it's an experience that makes you wonder about the passage of time and our own history.
如果你有幸近距离观赏一幅岩石艺术，你就知道，这种经历会让你对时间流逝和历史产生疑问。
But rock art also has a practical value for researchers and let's start by considering why that is.
但对研究人员来说，岩石艺术也有实用价值，我们先从原因开始讲起。
Firstly, it provides vital information about the way that people evolved - information not always easily obtainable from excavated artifacts alone.
首先，岩石艺术为人类进化方式提供了重要信息，要想仅仅从出土文物中获取这些信息也不是易事。
Secondly, rock art tells us about migration: where people came from and where, perhaps, they went next.
其次，岩石艺术能告诉我们迁移的信息：人们从哪里来，下一步可能去哪里。
Rock art is found all over the world and this in itself is not surprising. But what is rather amazing, you might think, is how similar some images are, whether you're looking at a rock face in South Africa or standing inside a cave in Spain.
岩石艺术在全世界都有，就其本身而言并不令人惊讶。但令人惊讶的是，某些图像之间是多么地相似，不管是看南非的石像面具，还是身处西班牙的岩石洞穴里。
Let me give you an example. When our ancestors drew humans, they would often draw them as stick figures, but if they drew a face, then the eyes were almost always very prominent, very open and wide.
让我举个例子吧。我们的祖先在描绘人类形象时，他们通常会把人化成粗线条的简笔画，但假如要画人脸，几乎所有的眼睛都是非常突出的，睁得又大又圆。
And of course, animals are very common in rock art, but one animal which is very interesting to researchers is the lizard, because whenever you see a prehistoric painting of one, it's depicted either in profile or looking down on it from above.
当然了，动物形象在岩石艺术中也非常常见，但研究人员真正感兴趣的是蜥蜴，因为不管什么时候看一幅史前画作，蜥蜴都是侧面像或（人们）俯视着它。
And these drawings are produced by people of totally different cultural backgrounds. Amazing!
这些绘画的作者都来自完全不同的文化背景。太惊人了！
But how can this be the case - that similar artistic styles exist in such distant locations?
但这怎么可能呢——如此相似的艺术风格出现在相距甚远的不同地点？
In the past, archaeologists believed that trade must have brought people together, and that it gave them the opportunity to observe each other's culture, including art styles, but this didn't prove to be the case.
过去，考古学家认为，一定是贸易把人们聚在了一起，给人们提供机会观察互相的文化（包括艺术风格在内），但事实证明并非如此。
Recently researchers have come up with a new theory.
最近，研究人员提出一种新理论。
They believe that the brains of our ancestors evolved to notice certain images before others and this was important (actually essential) because in an environment full of constant danger, it was necessary for survival.
他们认为，我们祖先的大脑已经进化到一定程度，可以在别人之前注意到一些图像。而这是非常重要的（实际上，至关重要），因为，在险象环生的环境中，这对生存来说是非常必要的。
So the need to quickly recognise things that could be helpful or harmful could have had a great influence on rock art and explain why some images are more common across cultures than others.
所以，快速辨认出事物有益还是有害的必要性对岩石艺术产生了巨大影响， 这也揭示了为什么某些形象在某些文化中更为常见。
Later on, there would have been other reasons why communities produced art - certainly for spiritual and social purposes and no doubt for political, ones, too, as different tribes looked for allies and struggled against their enemies.
接着，人们创作艺术也出于其它原因：出于精神层面、社会层面，无疑还有政治层面的原因，因为不同的部落间寻求联盟，同时也在不断与敌人抗争。