003 恐龙的终结

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Will was riding back to school from a field trip to a museum

威尔正从博物馆的实地考察活动乘车回学校。

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" The Tyrannosaurus was amazing!" said Bobby, Will's best friend

"那只霸王龙太棒了！"威尔最好的朋友鲍比说。

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" It was scary!" Will said. He looked at a photo he'd taken of the dinosaur skeleton with his phone and then glanced at their homework

"它好吓人！"威尔说。他看了一眼自己用手机拍的恐龙骨架照片，然后瞥了一下他们的作业。

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" Do you know the answer to number five? Why did dinosaurs disappear?" he asked Bobby

"你知道第五题的答案吗？恐龙为什么会消失？"他问鲍比。

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" Let's answer these questions before we forget everything... or before I fall asleep! Buses make me tired."

"趁我们还没忘光……或者在我睡着之前，赶紧回答这些问题吧！巴士总让我犯困。"

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Will tried to focus on the worksheet, but soon his eyes were closed and his head was bobbing up and down with every bump in the road

威尔努力想把注意力集中在作业纸上，但很快他就闭上了眼睛，脑袋随着路上的每一次颠簸一点一点的。

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When Will opened his eyes, he wasn't on the bus anymore

当威尔睁开眼睛时，他已经不在那辆巴士上了。

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He was in an aircraft, flying slowly over a strange landscape. QT, his phone, spoke

他身处一架飞行器里，正缓慢地飞越一片奇异的风景。他的手机QT开口说话了。

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" Scientists think the world looked like this in the late Triassic, the period from about 250 to 200 million years ago."

"科学家们认为，世界在晚三叠纪，也就是大约2.5亿到2亿年前的时期，就是这个样子的。"

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" Huh? When?" Will said

"啊？什么时候？"威尔说道。

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" This airship is carrying us through time. Scientists talk about Earth's history using a special scale called geologic time

这艘飞行器正载着我们穿越时间。科学家用一种特殊的时间尺度——地质时间，来谈论地球的历史。

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See that display? It tells us what period of time we're seeing

看到那个显示屏了吗？它会告诉我们正在观看的是什么时期。

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Experts think dinosaurs, like those over there, appeared during the Triassic

专家认为，恐龙——比如那边那些——出现在三叠纪。

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But let's travel forward into the next period, when dinosaurs thrived."

不过，让我们向前去到下一个时期，恐龙繁盛的时期。”

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QT shined a light at the controls, taking over

QT朝控制器射出一道光，接管了操控。

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The display changed as the scenery outside shimmered and transformed

随着外面的景色闪烁变幻，显示屏也随之改变。

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" So is this the Jurassic?" Will asked

“那这是侏罗纪吗？”威尔问道。

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" Yes. It lasted until about 150 million years ago

“是的。它一直持续到大约一亿五千万年前。

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Some dinosaurs became gigantic, as you can see

有些恐龙变得非常巨大，正如你所见。

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Let's skip forward into the next period, the Cretaceous

让我们快进到下一个时期，白垩纪。

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At the end of the Cretaceous, 70 percent of the species on Earth died, including most dinosaurs."

在白垩纪末期，地球上70%的物种灭绝了，包括大多数恐龙。

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Will nodded." We learned that at the museum. But what made them disappear?"

威尔点了点头。“我们在博物馆学过这个。但是什么让它们消失的呢？”

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" Well, scientists have some theories, but they can't prove them

“嗯，科学家们有一些理论，但他们无法证明。

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One clue is an unusual layer of rock found all over the world

一个线索是在世界各地发现的一层不寻常的岩石。

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It's about 65 million years old and contains a lot of iridium, an element that's usually rare on Earth's surface

它大约有6500万年历史，含有大量的铱，这是一种在地球表面通常很稀有的元素。

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It's normally located deep inside the planet or in space, in some asteroids

它通常位于地球深处或太空中的一些小行星上。

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This layer of rock led to two popular theories about what caused the extinction."

这层岩石引出了关于灭绝原因的两个流行理论。”

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QT announced," Here we are — the end of the Cretaceous, 65 million years ago."

QT宣布：“我们到了——白垩纪末期，6500万年前。”

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The sky was dark, and they were hovering over a field of volcanoes." There's so much lava!" Will said

天空一片黑暗，他们在一大片火山上空盘旋。“好多的岩浆！”威尔说。

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" We are over India," QT said

“我们在印度上空，”QT说。

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" Some scientists believe these volcanoes contributed to the extinction, because they could have brought iridium to Earth's surface in lava

"一些科学家认为这些火山导致了灭绝，因为它们可能通过熔岩将铱带到地球表面。

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The volcanoes might have released enough ash and gases —

火山可能释放了足够多的火山灰和气体——

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which then blew around the whole planet — to create a greenhouse effect, trapping heat in the atmosphere

这些物质随后席卷了整个地球——从而产生了温室效应，将热量困在大气层中。

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A warmer climate would have made it hard for many species to survive."

变暖的气候会使许多物种难以生存。"

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" Wow," Will whispered, watching a dinosaur flee from the glowing-hot rock

"哇，"威尔看着一只恐龙躲避炽热发光的岩石，轻声说道。

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" But there is another possibility. Let me transport us to another part of the planet," QT said

"但还有另一种可能。让我把我们传送到地球的另一边去，"QT说。

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The ocean appeared on the phone's screen, and the world went pitch-black

海洋出现在手机屏幕上，然后世界变得一片漆黑。

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When it became light again, their aircraft was hovering high over a body of water

当再次变亮时，他们的飞行器正高高地悬停在一片水域上方。

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QT continued," Some scientists think a huge asteroid, about ten kilometers across, hit Earth near Mexico 65 million years ago."

QT继续说道："一些科学家认为，6500万年前，一颗直径约十公里的小行星击中了墨西哥附近的地球。"

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A giant rock flew through the air. Will yelled," Is that the asteroid?"

一块巨大的岩石划过空中。威尔大喊道："那就是那颗小行星吗？"

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" Yes. Scientists are pretty sure it hit Earth, but they can only guess what happened next."

“是的。科学家们相当确定它撞上了地球，但之后发生了什么，他们只能推测。”

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The aircraft shook as the asteroid crashed into Earth

随着小行星撞击地球，飞行器摇晃起来。

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QT went on," The asteroid might have created a huge fireball and then tsunamis

QT 接着说：“小行星可能形成了一个巨大的火球，然后引发了海啸。

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As hot pieces of the asteroid fell back to Earth, they could have started wildfires worldwide

炽热的小行星碎片落回地球时，可能在世界各地引发了野火。

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So at first the temperature of the world would have increased."

所以最初，全球的气温会上升。”

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The aircraft flew closer to the ground, along the shore

飞行器沿着海岸，向地面飞去。

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Will stared at the destruction caused by the asteroid." How long did this take?"

威尔凝视着小行星造成的破坏。“这花了多长时间？”

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" No one knows exactly — maybe weeks or months

“没人确切知道——也许几周或几个月。

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After the fires dust from the explosion might have blocked light from reaching Earth's surface

大火过后，爆炸产生的尘埃可能阻挡了阳光到达地球表面。

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In the following years, plants, which need light to make food, would have died

在随后的几年里，需要阳光制造养分的植物会因此死亡。

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Then plant-eating dinosaurs would have starved and died

然后植食性恐龙就会饿死。

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And then the meat-eating dinosaurs would have starved and died too."

接着肉食性恐龙也会饿死。"

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" How do we know that?" Will asked

"我们怎么知道的？" 威尔问。

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" We can guess when species lived based on their fossils and what layer of rock we find those fossils in

"我们可以根据化石和发现化石的岩层来推测物种生存的年代。

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The species that went extinct don't appear in rocks formed after 65 million years ago."

灭绝的物种不会出现在6500万年以后形成的岩石中。"

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Will thought about everything QT had said

威尔仔细思考着QT所说的一切。

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" But scientists aren't sure whether the volcanoes or the asteroid caused the dinosaur extinction?"

"但科学家们不确定是火山还是小行星导致了恐龙灭绝？"

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" It's possible both contributed. There are other factors and theories too," QT replied

"有可能两者都起了作用。还有其他的因素和理论，" QT回答。

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" For instance, some people think mammals ate so many dinosaur eggs that dinosaurs couldn't survive

"比如说，有人认为哺乳动物吃掉了太多恐龙蛋，导致恐龙无法生存。

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And we're not sure whether dinosaurs died suddenly

而且我们不确定恐龙是否是突然死亡的。

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They could have been dying off gradually before the volcanoes or asteroid became a problem."

在火山或小行星成为问题之前，它们可能已经在逐渐消亡了。"

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QT paused, and the scenery outside began to transform

QT停顿了一下，外面的景色开始变换。

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" We've jumped forward just a few years. See all those animals?

"我们往前跳跃了仅仅几年。看到那些动物了吗？

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Many mammals, frogs, crocodiles, and even some species of dinosaurs survived the extinction. But we don't know why."

许多哺乳动物、青蛙、鳄鱼，甚至一些种类的恐龙都在这次灭绝中幸存了下来。但我们不知道为什么。"

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Will remembered the ferocious-looking Tyrannosaurus at the museum and shuddered

威尔想起了博物馆里那只面目狰狞的霸王龙，不禁打了个寒颤。

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" Did some dinosaurs survive into modern times?"

"有些恐龙存活到了现代吗？"

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" Well, scientists are pretty sure birds evolved from dinosaurs, so technically they are dinosaurs

"嗯，科学家们非常确定鸟类是从恐龙进化而来的，所以严格来说它们就是恐龙。

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And modern crocodiles aren't dinosaurs, but they are very similar to the crocodiles that were alive 65 million years ago," QT said

而现代的鳄鱼不是恐龙，但它们和6500万年前存活的鳄鱼非常相似，" QT说。

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Suddenly something rose out of the water. Its jaws snapped shut on the tail of the aircraft!

突然，有东西从水里冒了出来。它的嘴巴猛然咬住了飞行器的尾部！

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" No!" Will shut his eyes, expecting the crocodile to pull them underwater

"不！" 威尔闭上眼睛，以为鳄鱼会把他们拖入水底。

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The aircraft shook and then was still. Will peeked and realized that the bus had jolted to a stop in front of the school

飞行器震动了一下，然后静止不动了。威尔偷偷一看，意识到是校车在学校门前猛地停住了。

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" Wake up!" Bobby said." I hope you had a nice nap!"

"醒醒！" 鲍比说。"希望你睡了个好觉！"

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" I had the strangest dream about dinosaurs. I don't think I'll ever forget the stuff I learned today!" Will said

"我做了一个关于恐龙的最奇怪的梦。我想我永远不会忘记今天学到的东西！" 威尔说。