跟读练习: How do we know what color dinosaurs were? - Len Bloch - 通过YouTube学习英语口语
C1
This is the microraptor, a carnivorous four-winged dinosaur that was almost two-feet long, ate fish, and lived about 120 million years ago.
34 句
如果句子过短或过长，请点击 Edit 进行调整。
1
This is the microraptor, a carnivorous four-winged dinosaur that was almost two-feet long, ate fish, and lived about 120 million years ago.
2
Most of what we know about it comes from fossils that look like this.
3
So, is its coloration here just an artist's best guess?
4
The answer is no.
5
We know this shimmering black color is accurate because paleontologists have analyzed clues contained within the fossil.
6
But making sense of the evidence requires careful examination of the fossil and a good understanding of the physics of light and color.
7
First of all, here's what we actually see on the fossil: imprints of bones and feathers that have left telltale mineral deposits.
8
And from those imprints, we can determine that these microraptor feathers were similar to modern dinosaur, as in bird, feathers.
9
But what gives birds their signature diverse colorations?
10
Most feathers contain just one or two dye-like pigments.
11
The cardinal's bright red comes from carotenoids, the same pigments that make carrots orange, while the black of its face is from melanin, the pigment that colors our hair and skin.
12
But in bird feathers, melanin isn't simply a dye.
13
It forms hollow nanostructures called melanosomes which can shine in all the colors of the rainbow.
14
To understand how that works, it helps to remember some things about light.
15
Light is basically a tiny electromagnetic wave traveling through space.
16
The top of a wave is called its crest and the distance between two crests is called the wavelength.
17
The crests in red light are about 700 billionths of a meter apart and the wavelength of purple light is even shorter, about 400 billionths of a meter, or 400 nanometers.
18
When light hits the thin front surface of a bird's hollow melanosome, some is reflected and some passes through.
19
A portion of the transmitted light then reflects off the back surface.
20
The two reflected waves interact.
21
Usually they cancel each other out, but when the wavelength of the reflected light matches the distance between the two reflections, they reinforce each other.
22
Green light has a wavelength of about 500 nanometers, so melanosomes that are about 500 nanometers across give off green light, thinner melanosomes give off purple light, and thicker ones give off red light.
23
Of course, it's more complex than this.
24
The melanosomes are packed together inside cells, and other factors, like how the melanosomes are arranged within the feather, also matter.
25
Let's return to the microraptor fossil.
26
When scientists examined its feather imprints under a powerful microscope, they found nanostructures that look like melanosomes.
27
X-ray analysis of the melanosomes further supported that theory.
28
They contained minerals that would result from the decay of melanin.
29
The scientists then chose 20 feathers from one fossil and found that the melanosomes in all 20 looked alike, so they became pretty sure this dinosaur was one solid color.
30
They compared these microraptor melanosomes to those of modern birds and found a close similarity, though not a perfect match, to the iridescent teal feathers found on duck wings.
31
And by examining the exact size and arrangement of the melanosomes, scientists determined that the feathers were iridescent black.
32
Now that we can determine a fossilized feather's color, paleontologists are looking for more fossils with well-preserved melanosomes.
33
They've found that a lot of dinosaurs, including velociraptor, probably had feathers, meaning that certain films might not be so biologically accurate.
34
Clever girls.
下载应用
AI 为你说出的每个句子打分
TRENDING
热门
为什么要通过这个视频练习口语？
通过观看这段视频，学习者不仅能了解恐龙颜色的科学根据，还能在真实语境中练习口语。在视频中，讲解者使用了丰富的科学术语和具体的例子，这为英语口语练习提供了良好的基础。通过重复和模仿视频中的表述，听众可以提高他们的英语口语表达能力，掌握专业领域的相关词汇和句型。此外，这种练习方法可以帮助学习者更有效地提升听力理解和发音能力，成为更自信的英语使用者。
语法与表达方式分析
在视频中，讲解者使用了一些关键信息和语言结构，这里列出几个进行分析：
- 疑问句结构 - 例如：“这是真的吗？”这样的疑问句可用于日常交流中求证信息。
- 时态的使用 - 讲解者运用了简单过去时，来描述已发生的事情，如“生活在约1.2亿年前”，帮助学习者理解过去事件的表述。
- 从句 - “当科学家研究它的羽毛印记时”，这种从句结构增加了句子的复杂性，同时也体现了在专业对话中如何嵌套信息。
- 比较结构 - 比较“现代鸟类”和“恐龙羽毛”的相似性，帮助学习者学习如何进行比较。
常见发音陷阱
在视频中存在一些可能对学习者构成挑战的词汇和发音，以下是几个重点：
- microraptor - 这个词的发音可能对非母语者来说较为困难，尤其是在重音和音节的分配上。
- melanosome - 较长且复杂的医学术语，学习者应分解成音节进行练习，以提高发音的准确性。
- iridescent - 这个词描述色彩变化，发音时需要特别注意元音的发音和音调的变化。
通过看YouTube学英语，学习者可以在实际语境中提高清晰度，并进行英语口语练习，提升他们的发音与表达能力，使学习更加有效。
什么是跟读法？
跟读法 (Shadowing) 是一种有科学依据的语言学习技巧，最初开发用于专业口译员的培训，并由多语言者Alexander Arguelles博士普及。这个方法简单而强大：您在听英语母语原声的同时立即大声重复——就像是一个延迟1-2秒紧跟说话者的影子。与被动听力或语法练习不同，跟读法强迫您的大脑和口腔肌肉同时处理并模仿真实的讲话模式。研究表明它能显着提高发音准确性，语调，节奏，连读，听力理解和口语流利度——使其成为雅思口语备考和真实英语交流最有效的方法之一。