听力原文
上一期风河的谜团，在这一期中能否得到解决？听听下文吧。还有我们也许说不定会深入怀俄明州的盆地，看看里面有什么东西等待着我们。

... in the west. When they came to the area around the Owl Creek Mountains, they assumed there were two rivers. North of the mountain flowed a river which they named Bighorn, thinking it was different to Wind River in the south. But later survey showed that the Bighorn and Wind River are in fact one river that channeled through the mountain.

Recently, geologists have come up with a possible answer, an answer that could also explain what happened to the once towering peaks of the Rockies. They proposed that millions of tons of rock eroded away, filled in the valleys and covered the lower parts of the mountains. It completely changed the terrain.

"At one point in ancient history, the basins in Wyoming were filled with sediments that had eroded off the mountains. This allowed the river to be at a higher plain and meander wherever it wanted to be on its course."

As the water flowed, it carved deep into the sediments and rock underneath.

"Eventually it cut down a channel into the mountain and eventually excavated right through the mountain."

But this is just a theory. Now geologists needed to find proof on the ground. The search is on for the rock that eroded from the early Rockies. The investigation moves to a series of thousand-foot-tall hills in the Powder River Basin in Wyoming. Known as the Pumpkin Buttes, they stand tall in an otherwise wide, empty landscape. Hidden behind the horizon are the Bighorn Mountains - the nearest range of the Rockies. These hills are not formed from solid rock, but a collection of rubble.

"This rock, we find all over the top of Pumpkin Buttes in Wyoming, is a granite, the closest granite we find to the series of the Bighorn Mountains nearly 100 miles to the West."

小编有约：在一次又一次的猜想和论证下，咱们和记者一起发现谜团，然后解开谜团。我想说当福尔摩斯的感觉还真不差。但似乎本期的问题记者并没有解答论证出来，所以Daisy很期待这个答案。你呢？

课后题目：这次Daisy要考察考察大家的地理知识，请问在本期文章中出现了Wyoming的哪些地名？听一听找一找吧。

课后答案
呵呵~~答案就是"Owl Creek Mountains, Wind River, Powder River Basin, Pumpkin Buttes, Bighorn Mountains" 。
看看他们分别在文中的哪些地方出现。

参考译文
......在西部，他们来到猫头鹰溪山脉周围地区。假设有两条河，流入北边山脉的那条河，命名为大角，并且与南边的风河是完全不同的。但后来的调查表明，大角与风河实际上是同一条河流，只是在经过这些山时才分开的。

最近，地质学家想出一个可能的答案，也许可以解释为什么曾经高耸的落基山脉会下降。 他们认为，数百万吨的岩石受到侵蚀，填充了山谷以及覆盖了山的底部。最终它改变了这里的地形。

“在历史上，曾有一段时间，怀俄明州的盆地充满了被侵蚀了的落基山脉沉积物，使得这里的河可以在更高的平原上流淌，也不论在什么情况下，都可以蜿蜒缓慢地向前流动。”

水的流动使水深深地侵入这些沉积物和岩石的下方 。

“最终，它形成了一条进山的渠道，并且通过了这座山脉。”

但这仅仅是一个推测。现在，地质学家需要找到证据证实这个推测。从早期被侵蚀了的落基山脉岩石开始。我们调查到了一群千英尺高的小山，它们在怀俄明州的粉河盆地。这些山被称为南瓜巴茨山，屹立于这片宽广空旷的土地上。隐藏在地平线背后的是大角山，这是离落基山最近的山脉。这些小山不是由坚硬的岩石组成，却是一群碎石的堆积物。

“但在南瓜巴茨山的山顶却都找到了花岗岩石。同样发现了花岗岩石并且离这里最近的地方是，大角山脉以西约100公里处。”

重点讲解
注释：① assume vt. 承担；假定；采取；呈现 vi. 装腔作势；多管闲事
例句：
1. We cannot assume anything in this case.
在这种情形下我们无法作任何揣测。
2. I assume you've decided against buying a new car.
我想你已经决定不买新汽车了。

② come up with 提出；想出；赶上
例句：
1. The programmer come up with a solution to the system problem.
程序员想出了一个解决系统问题的办法。
2. I had to run to come up with him.
我得跑才能赶上他。
3. No one have come up with a convincing explanation of why dinosaur die out.
尚未有人能对恐龙的灭绝作出一个令人信服的解释。

③ filled with 充满；装满
例句：
1. My room is filled with the odour of roses.
我的房间里充满了玫瑰花的香味。
2. She was filled with the aspiration to succeed in life.
她渴望有所成就。
3. Children like books filled with illustrations.
孩子们喜欢插图丰富的书。

句子讲解：

1. Recently, geologists have come up with a possible answer, an answer that could also explain what happened to the once towering peaks of the Rockies.

　　【结构简析】 Daisy会先找主干，"geologists have come up with a possible answer"。后面是由"that"引导的名词性从句，用来解释说明"answer"是什么样的。

　　【参考译文】 最近，地质学家想出一个可能的答案，也许可以解释为什么曾经高耸的落基山脉会下降。

　　2. "This rock, we find all over the top of Pumpkin Buttes in Wyoming, is a granite, the closest granite we find to the series of the Bighorn Mountains nearly 100 miles to the West."

　　【结构简析】这句话中有一句插入的话，它是非限制性定语从句。补充说明发现这块岩石的地点。后面一句话是说他们同样能找到花岗岩的地方与现在这个地方的距离。这样好引出下面要讲的内容。

　　【参考译文】“但在南瓜巴茨山的山顶却都找到了花岗岩石。而同样发现了花岗岩石并且离这里最近的地方是，大角山脉以西约100公里处。”