Shadowing Practice: Why Are There No Holes Around Trees? - Learn English Speaking with Video
Choose a practice mode
Each mode opens a full-screen practice room.
98 sentences
If sentences are too short or too long, click Edit to adjust them.
1
Trees are the heaviest and largest living things on Earth, with the most massive tree weighing almost 2,000 tons – as much as ten blue whales.
2
But instead of floating weightlessly in the ocean it reaches 25 stories into the sky, held in place by surprisingly shallow roots.
3
You’d think trees grow from the ground because, well, they are made of stuff and there is stuff in the ground – but if something so massive and huge ate something down below, it would have to leave holes.
4
Instead trees are growing by literally eating thin air!
5
But this is only half of the story because down in the ground, roots are mining rocks in ways weirder than you can imagine.
6
How does this work?
7
How to Eat Air to Grow Huge Carbon is the most valuable material for living things.
8
A chemical multi tool you can make almost everything from – and a good amount of it just floats around in the air and the oceans.
9
What makes plants so incredibly successful is that over a billion years ago their ancestors became better than any other living thing at harvesting carbon.
10
They used it to grow and grow and grow.
11
Today plants make up 80% of the biomass on earth and are the basis for all complex life – all animals eat either plants or animals that eat plants, to get the carbon they need.
12
Trees are an especially ingenious way plants found to harvest massive amounts of carbon.
13
Trees are big and heavy and so they need a lot of material.
14
But the atmosphere is only about 0.04% CO₂.
15
425 CO₂ molecules per million molecules in the air.
16
To get a single tonne of carbon a tree has to process 6000 tons, or 5 million cubic meters of air!
17
This is a lot.
18
So trees developed sophisticated biological industrial megalopolises: Their crowns.
19
A huge industrial park network, made from dozens of branches, subbranches and hundreds of thousands of twigs that can sense the sun and shape the tree to grow towards it in slow motion.
20
They are carrying up to a million leaves, the industrial parks where a tree eats and builds, consuming extreme amounts of resources from the air and fed by the roots down below while vomiting waste and changing the climate around them.
21
Let’s zoom into a single leaf.
22
It is made from hundreds of millions of factory cells and optimized to have as much surface area and be as thin as possible to harvest sunlight.
23
While your skin is hundreds of cells thick, a leaf can be just ten cells top to bottom.
24
On their top leaves have only a single, ultra thin layer of protective transparent “skin” cells that let light through and keep water in.
25
Below them are layers of factory cells, filled to the brink with chloroplasts that do the actual work.
26
Beneath them a spongy layer of loose cells enables gases to travel around.
27
The whole leaf is traversed by a network of vein-like superhighways, that carry sugars back down and bring water and minerals up from the roots.
28
At the bottom is another protective layer of cells interrupted by hundreds of thousands of stomata – tiny mouths opened and closed by two guard cells that look a bit like lips.
29
Each day an adult tree pulls up dozens of liters of water all the way from its roots in the ground to these veins, where about 95% of it is sweated out through hundreds of billions of these tiny mouths.
30
This cools the leaf factories, which need to stay in direct sunlight as long as possible, and the air around the tree.
31
And it surrounds the tree with an invisible mist.
32
The vapor from a forest of billions of trees can seed clouds and create rain.
33
Rainforest is literal – without the trees the amazon would be a sad dry shrubland or desert.
34
The other 5% of the water is used to keep the cells alive and to power the factories where the magic happens: Photosynthesis.
35
We are not going to explain the details here, but in a nutshell, with the energy from the sun, water molecules are split into hydrogen and oxygen.
36
The oxygen is ejected, while the leftover hydrogen and CO2 are forged and reduced into glucose – a simple sugar that’s both battery and building block.
37
And the source of most carbon in the world for most animals.
38
Oxygen is not just garbage to the tree though.
39
To actually use the energy stored in the glucose, the tree has to burn the sugar, just like we humans do, with cellular respiration.
40
So all living cells in the tree suck in oxygen – through the tiny leaf mouths, cracks in the bark, and even root tips tapping into tiny air pockets hidden in the soil.
41
This respiration runs nonstop, and especially at night when the leaf factories stop production.
42
Trees actually reabsorb some of the oxygen they produce and almost all of the rest gets used up by microbes and everything else breathing nearby.
43
Most of the world's free oxygen doesn't come from trees but from algae and cyanobacteria in the oceans.
44
But this is only half of the story because the even more insane parts of trees are the second invisible crown: the underground empire of the roots.
45
Most of the water a tree needs comes from rainfall, which soaks mainly into the upper layers of soil.
46
Annoyingly for trees their crowns are big umbrellas, so their roots need to spread out far and wide towards the side.
47
About 50% of their roots are packed into the top 25 centimeters of soil.
48
They are not a mirror image of the crown, but a dense, tangled mat, deeply intermingled with their neighbours’.
49
Only if it’s very dry do roots grow straight down to tap hidden water reserves, in extreme cases more than 20 stories deep.
50
But this is a rare exception.
51
Most roots reach down 7m.
52
But roots have a far more complex job than just catching water.
53
Just like you can’t build a city from only bricks and steel, trees also need some rare materials: phosphorus to build DNA, nitrogen for proteins and many more.
54
And all of these are stealthily buried underground.
55
Rocks, dry patches, nutrients, and rival roots are all scattered unpredictably and chaotically.
56
To navigate this shifting maze, roots evolved a specialized sensor at their very tip: the root cap.
57
Each cap is filled with gravity-sensing cells, in which tiny dense particles sink like pebbles settling in a jar of water.
58
So the root always knows which way is down.
59
As it pushes forward, specialized cells detect moisture, temperature, chemical gradients and the smallest vibrations from water.
60
This raw data flows into the root’s command center just behind the tip, where cells produce electrical pulses and move transmitter chemicals around.
61
Signals from the soil are processed, interpreted and turned into decisions about where to grow.
62
A single tree has hundreds of thousands of these command centers and they seem to share information with each other.
63
Once a root has chosen a path, fuzzy little drinking straws called root hairs, loaded with enzymes and transport proteins, begin soaking up water and dissolved minerals.
64
But many essential nutrients are locked away in solid rock.
65
So roots evolved to move into the finest cracks.
66
Once in, they fill with water and swell like tiny hydraulic jacks, creating enough pressure to break even the hardest rock.
67
Next they release a mix of acids that seep into the fractures and dissolve the bonds that hold nutrients in place.
68
Claw-like molecules grab them and pull them in before they can slip away.
69
This sophistication really is stunning but it gets even wilder.
70
Even with all these tools, to really thrive, the tree needs allies.
71
And it found them: fungi.
72
The underground networks of fungi can stretch for kilometers.
73
They are so small that they can go where roots can’t, slipping between grains of soil to reach distant pockets of nutrients.
74
But they need food.
75
So hundreds of millions of years ago roots and fungi formed a trade alliance.
76
The trees provide a cut of the sugars they produce far up in the sky and fungi collect and give them nutrients and water in return. Some fungi grow directly into the root’s cells, building tiny trade posts, where sugars and minerals change hands.
77
Others wrap themselves around root tips, weaving between their outer layers, insulating delicate tissues and protecting them against microorganisms.
78
Today there are thousands of fungal tree ally species, each with its own specialties.
79
Some only partner with specific tree species, while others are happy to work with almost anyone.
80
These connections often knit the roots of many trees together into vast underground networks.
81
Their scale is gigantic.
82
In just one cubic meter of healthy forest floor, fine tree roots can stretch for several kilometers and for every kilometer of root, there can be hundreds of kilometers of fungal networks.
83
It’s one of the largest and most intricate living structures on Earth, and may even connect whole forests.
84
We are only beginning to understand how complex and intricate the relationships between trees, their offspring, relatives and rivals, microbes and fungal networks are.
85
But the more we’ve learned over the last few decades, the clearer one thing has become: Trees are just so incredibly wild.
86
And we have so much more to learn.
87
People once believed that all fungi — even those allied with trees — were just strange plants.
88
But then, some incredible minds discovered that they were actually an entirely different life form!
89
This breakthrough in understanding was powered by a combination of technical knowledge and problem-solving skills.
90
And you can start building both right now, for free, with Brilliant.
91
Brilliant helps you excel in math, science, and computer science through visual, interactive learning that’s personalized for you.
92
And as you master new concepts, you’ll also become a better thinker and problem solver — and start seeing the world in a whole new way.
93
Brilliant is designed to be highly effective.
94
You learn by doing — a method shown to be far more powerful than passive learning.
95
It also tailors your experience: starting you at the right level, customizing your practice sets and reviews, and helping you advance at your ideal pace.
96
Whether you’re mastering fundamental math, algebra, or calculus, diving into algorithms or exploring everyday physics, Brilliant will help you reach big learning goals – and give you the skills to make breakthroughs of your own.
97
To explore everything Brilliant has to offer for free for a full 30 days, go to brilliant.org/nutshell, scan the QR code on the screen, or click on the link in the description.
98
Brilliant’s also given our viewers 20% off an annual Premium subscription, which gives you unlimited daily access to everything on Brilliant.
Download App
Everything you need to speak fluently
AI PronunciationScore every sentence
IPA PracticeMaster every sound
VocabularyBuild your word bank
Vocab GameLearn while playing
📺 Same Channel
B227
Your Skeleton Is Electric
Daily ConversationUniversity StudentsWorking Adults
C1114
Could Humans Evolve Flight?
Daily ConversationUniversity StudentsWorking Adults
B2133
Can Earth Run Out of Water?
Daily ConversationUniversity StudentsWorking Adults
B232
Your Brain Peaked at Birth
Daily ConversationUniversity StudentsWorking Adults
C135
Why Ebola Keeps Coming Back
Daily ConversationUniversity StudentsWorking Adults
B27
3 Reasons Why Nuclear Energy Is Terrible! 2/3
Daily ConversationUniversity StudentsWorking Adults
B21
Your Brain on Magic Mushrooms
Daily ConversationWorking Adults
C19
Would You Upload Your Mind?
Daily ConversationUniversity StudentsWorking Adults
B2555
What If You Never Slept?
Daily ConversationUniversity StudentsWorking Adults
B264
What the Flu Does to Your Body
Daily ConversationUniversity StudentsWorking Adults
C11
The Rise of the Machines – Why Automation is Different this Time
Daily ConversationUniversity StudentsWorking Adults
B21
The Most Complex Language in the World
Daily ConversationUniversity StudentsWorking Adults
B25
Let’s Steal a New Moon
Daily ConversationUniversity StudentsWorking Adults
B2759
How Stress Changes Your Brain
Daily ConversationUniversity StudentsWorking Adults
B23
What Happens AFTER Nuclear War?
Daily ConversationWorking Adults
B21
3 Reasons Why Nuclear Energy Is Awesome! 3/3
Daily ConversationWorking Adults
B252
Can We Stop the Extinction?
Daily ConversationUniversity StudentsWorking Adults
B26
YOU Own the Moon. And Mars. And Venus.
Daily ConversationUniversity StudentsWorking Adults
B2209
The True Cost of War
Daily ConversationWorking Adults
B23
What Is Life? Is Death Real?
Daily ConversationUniversity StudentsWorking Adults
✨ Recommend Video
C14
106 sentences
Trees Are So Weird
IELTS PrepTOEFL PrepUniversity Students
C126
62 sentences
The use of soil to reduce carbon dioxide in the atmosphere | IELTS LISTENING TEST | SECTION-4
IELTS PrepTOEFL PrepUniversity Students
C19
48 sentences
Why Don't Blue Whales Eat Fish?
IELTS PrepTOEFL PrepUniversity Students
C12
99 sentences
Unlimited Resources From Space – Asteroid Mining
IELTS PrepTOEFL PrepUniversity Students
C114
316 sentences
The Most Controversial Idea In Physics
IELTS PrepTOEFL PrepUniversity Students
C15
465 sentences
Can trees save the planet? | DW Documentary
IELTS PrepTOEFL PrepUniversity Students
C136
90 sentences
How do bees make honey?
American AccentIELTS PrepTOEFL PrepUniversity Students
C12
31 sentences
bài học 13 - 2
IELTS PrepTOEFL PrepUniversity Students
C14
41 sentences
The Building Blocks of Everything: Matter & its Properties
IELTS PrepTOEFL PrepUniversity Students
B24
200 sentences
Why Are 96,000,000 Black Balls on This Reservoir?
IELTS PrepTOEFL PrepUniversity Students
C13
55 sentences
Vol 3 - test 6 - section 4
IELTS PrepTOEFL PrepUniversity Students
C12
143 sentences
You Live Inside a Cosmic Hole... And there's a problem
IELTS PrepTOEFL PrepUniversity Students
Vocabulary and speaking notes for this lesson
This C1 speaking lesson is built on the video “Why Are There No Holes Around Trees?”. The speaker keeps coming back to these words: tree, root, cells, grow, hundreds. This video has 98 sentences and 1791 words to shadow. The speech runs for 11:04. The speaker talks at a natural 162 words per minute, close to everyday conversation. Only 77% of the words are among the 3,000 most common in English, so the vocabulary is demanding.
Key vocabulary in this video
The 15 most advanced words in the video, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| fungi noun | /ˈfund͡ʒi/ | A style of folk and popular music from the Virgin Islands, traditionally performed by bands consisting of banjo, guitar, ukulele, and washboard with various… |
| nutrient noun | /ˈnuː.tɹi.ənt/ | A source of nourishment, such as food, that can be metabolized by an organism to give energy and build tissue. |
| molecule noun | /ˈmɑ.lɪ.kjul/ | The smallest particle of a specific element or compound that retains the chemical properties of that element or compound; two or more atoms held together by… |
| fungal adjective | /ˈfʌŋɡəl/ | Of or pertaining to a fungus or fungi. |
| mineral noun | /ˈmɪn.ə.ɹəl/ | Any naturally occurring solid material that has a (more or less) definite chemical composition and characteristic physical properties; especially, an inorganic… |
| harvest noun | /ˈhɑɹ.vəst/ | The process of gathering the ripened crop; harvesting. |
| microbe noun | /ˈmaɪkɹoʊb/ | Any microorganism; (loosely, nonscientifically) especially, a harmful bacterium. |
| nutshell noun | /ˈnʌt.ʃɛl/ | The shell that surrounds the kernel of a nut. |
| respiration noun | /ɹɛspɪˈɹeɪʃən/ | The process of inhaling and exhaling. |
| specialize verb | /ˈspɛʃəˌlaɪz/ | To narrow in scope. |
| intricate adjective | /ˈɪn.tɹɪ.kət/ | Having a great deal of fine detail or complexity. |
| cubic adjective | /ˈkju.bɪk/ | Used in the names of units of volume formed by multiplying a unit of length by itself twice. |
| glucose noun | /ˈɡluː.kəʊz/ | A simple monosaccharide (sugar) with a molecular formula of C₆H₁₂O₆; a principle source of energy for cellular metabolism. |
| vein noun | /veɪn/ | A blood vessel that transports blood from the capillaries back to the heart. |
| evolve verb | /ɪˈvɑlv/ | To move (something) in regular procession through a system. |
Phrasal verbs you will hear
| Word | Pronunciation | Meaning |
|---|---|---|
| back down verb | To take a less aggressive position in a conflict than one previously had, or has planned to have. | |
| pull up verb | /ˌpʊl ˈʌp/ | To lift upwards or vertically. |
| push forward verb | To continue to act or do something, especially with a lot of effort | |
| reach down verb | To take an item down from a high shelf or the like. | |
| spread out verb | Become further apart. | |
| use up verb | To consume, deplete, expend, or exhaust. |
Grammar in this video
The structures the speaker uses most, with the exact words from the video:
| Structure | In the video |
|---|---|
| Passive voice be + past participle — the focus is on what happens, not who does it | are made · is made · is traversed |
| Present perfect have/has + past participle — a past action that still matters now | has chosen · we've learned |
Pronunciation to watch
The speaker uses 7 contractions and reduced forms, such as can't, doesn't, we've. Say them the short way, as you hear them.
- The “th” sounds: breakthrough /ˈbɹeɪk.θɹuː/, thrive /θɹajv/, algorithm /ˈælɡəɹɪðm̩/
- The “sh” and “zh” sounds: nutshell /ˈnʌt.ʃɛl/, respiration /ɹɛspɪˈɹeɪʃən/, specialize /ˈspɛʃəˌlaɪz/, shallow /ˈʃæloʊ/, subscription /səbˈskɹɪpʃən/
- Long words — get the stress right: respiration /ɹɛspɪˈɹeɪʃən/, invisible /ɪnˈvɪzəb(ə)l/, annoyingly /ʌˈnɔɪjɪŋli/, personalize /ˈpɜː.sə.nə.laɪz/, interactive /ˌɪn.tɚˈæk.tɪv/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
- Record yourself and compare with the original, paying attention to words like fungi, nutrient, molecule.
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.