『新东方在线托福听力』为托福考生准备了ETS托福TPO/Official 36 Lec 2听力练习：Why does the professor mention limestone?原文题目答案解析，TPO/Official 36 Lec 2听力原文范文音频翻译。

托福TPO/Official 36 Lec 2听力原文Why does the professor mention limestone?【新东方在线】

旁白：请听一堂考古学讲座的节选。

Listen to part of a lecture in an archaeology class.

教授：当然了，有时候我们的确在做实地考察的时候有了重要的发现，但是往往我们对于去看哪里只是有一个模糊的想法。

Professor: Sure. Sometimes we do just stumble onto an important find when doing field research, but usually we've got at least a vague idea of where to look.

如果有了新的科学技术的话……嗯……那就可以了。

这是一个可以解释我所说的东西的故事。

Here's a story that illustrates what I mean.

这个故事是关于玛雅人的。如你们所记，玛雅人繁荣于美国中部，并拥有在艺术、建筑、天文方面十分先进的文化……

It's about the Mayans, who, as you remember, flourished in Central America and had a culture that was quite advanced in art, architecture, astronomy...

我们知道尽管栖息地经常干旱，土壤贫瘠，他们的人口还是在几个世纪之后增长到了百万，直到大约1200年前，他们整个文明突然灭绝了，我们还不知道灭绝的原因。

We know that despite regular droughts and poor soil, their numbers grew into the millions over the centuries until about 1,200 years ago when their entire civilization just seemed to disappear, and we are not sure why.

然后一个名为William Saturno的考古学家就在San Bartolo小城的Guatemala地区寻找玛雅遗迹。

So an archaeologist named William Saturno1 goes looking for ancient Mayan ruins in Guatemala near a town called San Bartolo.

在热带密林里经过几天艰苦跋涉之后，Saturno在树荫下停留休息，他发现自己坐在了一处古老的玛雅寺庙遗迹上，那是一座25米高的金字塔。

And after several days of extremely difficult hiking through the thick rainforest, Saturno stops to rest in the shade and finds himself sitting in what turns out to be an ancient Mayan temple, a pyramid 25 meters high.

在寺庙的高墙之内，Saturno发现了一些古老的文字，还有巨大的画着华丽人像的墙壁。这些描述了玛雅人认为的世界被创造的神话。

And inside, on the walls of this temple, Saturno finds some ancient writing and also this enormous mural with elegant figures depicting a Mayan myth of the creation of the world.

这一切都被画在石膏上，已经有两千多岁了，这就使得它成为了被发现的最古老的玛雅艺术品。至少是保存完好的最古老的玛雅艺术品。实际上，也是最完美保存下来的并且最重要的艺术品之一。

And it's all painted on plaster that's over 2,000 years old, which makes it the oldest Mayan artwork ever found, at least in good condition, and in fact, one of the most perfectly preserved and extremely important find.

学生：哇！你有关于它的照片吗？

Student: Wow! Do you have a picture of it?

我没有……我在这里还要说一件事。

I don't...there's a point I want to make here.

有人在美国国家航空航天局读过关于Saturno的发现的文章，并感到很激动，因为航天局使用一种名为遥感的技术对这个地区拍摄了几张照片。

It happens that someone at NASA, the United States Space Agency, reads about Saturno's discovery and gets very excited 'cause the space agency has just produced some images of this area using a technique called remote sensing.

这时，飞机上的设备和卫星调查了这片区域。

That's when instruments on planes and satellites survey areas on the ground.

遥感的最新改进是红外成像，这个技术相当新。

And the newest twist on remote sensing, quite new, is infrared imaging.

除了常规的摄像，卫星照相机使用红外线拍摄照片，红外线对于人眼是不可见的，但是计算机可以加工这种照片，使其对于我们可见。

Instead of taking regular photographs, the satellite cameras take pictures using infrared light, which is invisible to the human eye, but computers can then process these images so our eyes can see them.

使用红外成像，基于卫星的遥感仪器发现了最终被发现是储水仓库系统和水道，这些水道是玛雅人建造来浇灌他们干涸的土地的，这就解释了玛雅人是如何养活如此巨大的人口的。

Using infrared imaging, the satellite-based remote sensing instruments revealed what turned out to be traces of water storage systems and canals, canals that the Mayans built to irrigate their parched soil, which helps explain how the Mayans could feed such a large population.

红外成像也发现了古老的道路，这些道路把玛雅城市连通起来。

The infrared images also revealed ancient roadways that had tied Mayan cities together.

航天局的人觉得Saturno会对于这些照片感兴趣，所以他们就把发现金字塔的San Bartolo地区的红外照片发给了他。

So people at the space agency figured Saturno would be interested and they sent him this infrared image of the area near San Bartolo where the pyramid temple was found.

这是一幅基于红外照片的伪彩图。

Now, this is a false color image based on an infrared photo.

绿色的丛林显示是蓝色和红色的，但也会呈现为黄绿色的小点。

So the greens of the jungle are shown mostly as blue and red, but notice also the spots of greenish yellow scattered here and there.

这显示出重要的植被的变色，至少是在红外成像下变色了。

These indicate significant discoloration in the vegetation, at least as it appears to infrared cameras.

Saturno注意到，一些变色地点和他发现金字塔的地点恰好吻合。

And Saturno notices that some of that discolorations located in exactly the spot where he found the pyramid temple.

所以他觉得，可能其他的变色地点也需要查一下。

So he figures, hey, maybe some of those other yellow spots are worth investigating.

长话短说，他查看了三个植被变色的地点，发现了三个地点之下的确有一处玛雅遗迹。

Well, long story short, he checks out three different spots where the photo shows discoloration and finds an ancient Mayan site overgrown with vegetation at every single one.

更深入的调查展示了红外照片上变黄色的地区和藏在地下的玛雅遗迹之间有很大的关联。

Further exploration shows a perfect correlation between yellow spots on the infrared image and Mayan ruins hidden in the jungle.

学生：所以是什么导致植被变色的呢？

Student: So what caused those spots to look different?

教授：Saturno相信玛雅人用来建造建筑的石灰石和石灰石膏……

Professor: Well, Saturno believes the limestone and lime plasters that the Mayans used to build their structures...

经过长久的时间，这种石灰石腐烂掉，渗进土壤，改变了土壤的化学成分。

Over time, uh, this limestone decayed and seeped into the soil and changed the soil's chemistry.

腐坏的石膏产生的碳酸钙可能会被树木的根吸收，运输到树叶上，让这些树木在红外照射下放出比周围的树木更加明亮的光。

Then calcium carbonate from the decaying lime plaster might have been taken out by the roots of the trees growing there, uh, up into their leaves, and made them give off infrared light much more brightly than the surrounding vegetation.

红外感知设备就可以检测到这种现象。

And infrared sensing technology can detect this.

学生：所以……是这样……危地马拉是不是唯一一处考古学家运用遥感技术探索的地区？

Student: So…like…is Guatemala the only place where archaeologists have used remote sensing?

教授：不，这个技术在美国中部的其他地方也被应用了，在巴西、玻利维亚、柬埔寨也是。

Professor: No. This technique has been used in other parts of Central America too, and also in Brazil, Bolivia, Cambodia.

只要是丛林掩盖了古代遗迹的地方都可以使用。

It can be used anywhere the rainforest has obscured ancient ruins.

结果是惊人的！就像是Saturno发现的其他玛雅庙宇一样，感谢遥感技术，他曾经每日在它们的上面行走而不知其存在，直到他看到了那片地区的红外成像！

And the results can be amazing! Like another Mayan temple that Saturno found, thanks to remote sensing, he had walked right by it every day for five years and had no idea it was there, until he saw an infrared image of the area!

According to the professor, what is the most significant aspect of the mural that William Saturno found near San Bartolo, Guatemala?

Why does the professor mention roads and canals?

After Saturno found the pyramid temple near San Bartolo, what guided his search for other ancient Mayan sites?

Why does the professor mention limestone?

Listen again to part of the Lecture.Then answer the question. Why does the professor say this:

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