听力原文

知道了早期落基山脉下降的原因，会带给我们怎么样的启示？落基山脉经过了侵蚀后，接下来的火山作用又带给了这座山什么样的变化呢？经历了侵蚀和火山作用，落基山脉还会经历什么呢？值得期待！

This fine-grained ash suggests huge volcanic eruptions nearby. They spewed out（喷射） thick clouds of hot air, ash and volcanic rock which settled on the ground. Radiocarbon（ [核] 放射性碳）dating the rock revealed that it happened 25 million years ago.

"Ash was deposited as it came out of the sky as plumes（羽毛）. Most of it came from the West and was deposited in the basins across Wyoming."

After the lower Rockies were buried by their own rock, volcanic ash settled on top and covered the area with a thick white sheet.

"At the time of the deepest basin filled with this volcanic material, all you would see in this area was the very tops of the peaks exposed, the rest would be large extensive lateral ash sheets."

Erosion and volcanism（n. [地质] 火山作用） completely transformed the terrain and buried the Rockies. But then, over millions of years, rivers flushed out the eroded rock.

Most of it is thought to have ended up in the Missouri and Mississippi Rivers, from where it was transported into the sea. What's left are the mountains we see today. This also confirmed the theory geologists had about the formation of Wind River Canyon, the incredible amount of infield （耕地）buried the Owl Creek Mountains. Wind River flowed on top and began carving into the mountains, creating the canyon we see today.

The investigation into what happened to the early Rocky Mountains reveals two major clues. Granite, found on the Pumpkin Buttes, is evidence that the early Rockies dumped their eroded rock into the basins. Wind River Canyon, cutting straight through the Owl Creek Mountains is evidence that the Rockies were buried by their own debris. The once mighty Rockies had now been cut down to nearly half their original size, but the story was far from over. Before they became the mountains we know today, they would have to endure an even greater assault.

小编有约：早期落基山脉的变迁史让人着迷，就如同一位沧桑的老人，它的故事给Daisy的感觉就是你不探索则以，如果开始听了，就会坚持听下去，然后悟出自己的道理，一切事物都有自己的衰荣史，最开始从海底升起来，到慢慢的经历毁灭性的打击，一直保存到我们现在看到的山，虽然高度已减少一半，但是它依然在这个世界存在着，好多人遭受到了打击，选择一条不归路。当然这只是小编的意见，欢迎大家各抒己见。

课后题目：这次Daisy想要问问大家有仔细听吗？对于早期落基山脉历史变迁的调查，结果揭示出了两个主要线索。能告诉Daisy是哪两个主要线索吗? 可以用自己的话来表述，只要意思差不多就行哦。

听力答案

呵呵~~答案就在" Granite, found on the Pumpkin Buttes, is evidence that the early Rockies dumped their eroded rock into the basins. Wind River Canyon, cutting straight through the Owl Creek Mountains is evidence that the Rockies were buried by their own debris." 看看在文中哪里？仅供参考！

参考译文

细颗粒的灰暗示着这附近有大的火山喷发。火山喷射出的热空气、火山灰散布在空气中还有地面上厚厚一层的火山岩。岩石中放射性的碳元素可以让我们知道这块岩石已有2500万年的历史。

灰尘犹如天空中漂着的羽毛。他们大部分来自西边，而且覆盖了怀俄明盆地。

较低的落基山脉被自己风化掉的岩石灰掩埋后，位于顶部的火山灰则被厚厚的积雪覆盖。

当最底的盆地被火山喷发出的物质所掩埋，在这片地方你看到的山峰就很高，显得很突兀，四周被火山灰笼罩得既大又宽，就像灰色床罩。

侵蚀和火山作用彻底改变了这里的地形，也掩埋了落基山脉。但是，经过数百万年，河流从被侵蚀的岩石中流出。

人们认为大多数的河流流入密苏里州和密西西比河，在那里和其他河流汇合注入海中。接着就是我们今天所看到的一切。这也证实了地质学家关于形成风河峡谷的猜想，大量的耕地埋葬了猫头鹰溪山脉，这个数量令人难以置信。风河在上边流动，它流过这些山脉的同时也在雕琢着这些山脉，慢慢地就形成今天我们所看到的峡谷。

关于早期落基山脉历史变迁的调查，结果揭示出了两个主要线索。南瓜巴茨山的花岗岩，向我们证实早期落基山脉那些被侵蚀了的岩石聚集到了低洼的盆地。风河峡谷，就像刀切过一样笔直的流过猫头鹰溪山脉，这向人们证明落基山脉被自己的残骸所覆盖。曾经雄伟的落基山脉现已削减了近一半的大小，但故事却远未结束。成为今天呈现在咱们面前的落基山脉，它将会遭受到更为严厉的打击。

重点讲解

注释：① deposite vt. 放置，存储
例句：
1. I had to deposit 10% of the price of the house.
我必须先付房价的10%作定钱。
2. You may deposit your valuables in the hotel safe.
您可以将您的贵重物品放在旅馆的保险柜里。

② flush n. 激动，洋溢；面红；萌芽；旺盛；奔流
vt. 使齐平；发红，使发亮；用水冲洗；使激动
vi. 发红，脸红；奔涌；被冲洗
adj. 大量的；齐平的；丰足的，洋溢的；挥霍的
例句：
1. She shows a flush of joy at his coming.
对他的到来她表现出一阵兴奋。
2. Rivers flush with the spring rains.
因春雨而上涨的河水

③ assault n. 攻击；袭击
vt. 攻击；袭击
vi. 袭击；动武
例句：
1. After the assault was successful, the last four guards had surrendered.
袭击得手之后，最后四个卫兵投降了。
2. The commander decided to assault the enemy in the darkness.
指挥官决定夜袭敌军。

句子讲解：

1. They spewed out thick clouds of hot air, ash and volcanic rock which settled on the ground.

【结构简析】句中的"which"从句是一个定语从句，修饰前面的volcanic rock。

【参考译文】火山喷射出的热空气、火山灰散布在空气中还有地面上厚厚一层的火山岩。

2. This also confirmed the theory geologists had about the formation of Wind River Canyon, the incredible amount of infield buried the Owl Creek Mountains.

【结构简析】"geologists had about the formation of Wind River Canyon"在句中用来说明"theory" ,省略了关系词"that"，"buried"过去分词来修饰"infield"。

【参考译文】这也证实了地质学家关于形成风河峡谷的猜想，大量的耕地埋葬了猫头鹰溪山脉，这个数量令人难以置信。