E03 003 恐龙的终结

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0:06 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。
0:10 " 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。
0:16 " 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。
0:26 " 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。
0:32 " 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。"
0:40 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。
0:49 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。
0:52 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。
0:58 " 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。"
1:08 " Huh? When?" Will said "啊？什么时候？"威尔说道。
1:11 " 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。
1:21 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。
1:28 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。
1:34 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。”
1:39 QT shined a light at the controls, taking over QT朝控制器射出一道光，接管了操控。
1:42 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。
1:47 " So is this the Jurassic?" Will asked “那这是侏罗纪吗？”威尔问道。
1:51 " 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。
1:56 Some dinosaurs became gigantic, as you can see 有些恐龙变得非常巨大，正如你所见。
2:01 Let's skip forward into the next period, the Cretaceous 让我们快进到下一个时期，白垩纪。
2:05 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。
2:13 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？”
2:18 " 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。
2:22 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。
2:27 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。
2:36 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。
2:42 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。”
2:49 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。”
2:57 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。
3:06 " We are over India," QT said “我们在印度上空，”QT说。
3:10 " 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。
3:19 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——
3:23 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。
3:30 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。"
3:36 " 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。
3:41 " 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。
3:48 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。
3:53 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。
3:58 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。"
4:10 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？"
4:15 " 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。”
4:21 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。
4:25 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。
4:33 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。
4:40 So at first the temperature of the world would have increased." 所以最初，全球的气温会上升。”
4:45 The aircraft flew closer to the ground, along the shore 飞行器沿着海岸，向地面飞去。
4:48 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？”
4:54 " No one knows exactly — maybe weeks or months “没人确切知道——也许几周或几个月。
4:58 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。
5:04 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。
5:11 Then plant-eating dinosaurs would have starved and died 然后植食性恐龙就会饿死。
5:14 And then the meat-eating dinosaurs would have starved and died too." 接着肉食性恐龙也会饿死。"
5:19 " How do we know that?" Will asked "我们怎么知道的？" 威尔问。
5:22 " 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。
5:29 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。"
5:36 Will thought about everything QT had said 威尔仔细思考着QT所说的一切。
5:38 " 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？"
5:45 " 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。
5:52 " 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。
5:59 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。
6:03 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。"
6:09 QT paused, and the scenery outside began to transform QT停顿了一下，外面的景色开始变换。
6:13 " 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？
6:18 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。"
6:26 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。
6:30 " Did some dinosaurs survive into modern times?" "有些恐龙存活到了现代吗？"
6:35 " 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。
6:43 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。
6:52 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！
7:00 " 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。
7:05 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。
7:13 " Wake up!" Bobby said." I hope you had a nice nap!" "醒醒！" 鲍比说。"希望你睡了个好觉！"
7:18 " 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。