TOEFL · Listening · 28 questions

TOEFL Listening Mock Test 7

Original listening and reading mock tests modelled on the published TOEFL iBT format.

This is an original practice test written by Loopy following the published format. It is not an official ETS test.

TOEIC® and TOEFL® are registered trademarks of ETS. IELTS is jointly owned by the British Council, IDP and Cambridge English. Loopy's practice tests are original and are not affiliated with or endorsed by these organisations.

Full-test audio

Conversation 1

  1. Question 1

    Why does the student go to see the professor?

    • ATo ask for advice on how to shorten her research proposal.
    • BTo request an extension on the paper's Friday deadline.
    • CTo change her paper topic from urban bees to another subject.
    • DTo get a list of books to include in her bibliography.
    Show transcript

    NARRATOR: Listen to a conversation between a student and a professor. STUDENT: Hi, Professor. Thank you for meeting with me during your office hours today. I wanted to talk about my draft proposal for the environmental science paper on urban bee populations. I am having some trouble with the assignment guidelines. PROFESSOR: Hello, Sofia. It is good to see you. Yes, I read your draft proposal, and your topic on urban bees is excellent. What exactly is the trouble you are having with the guidelines? STUDENT: Well, it is the page limit. Right now, my draft is eight pages long. But the project guidelines say the final paper must be exactly five pages. I am really worried because I do not know what I should cut out. Also, uh, I mean, I wanted to ask if the bibliography counts as part of those five pages. PROFESSOR: Ah, I see. That is a very common question. Let me reassure you: the bibliography does not count toward the five-page limit. That page is extra. But without the bibliography, your main text is still seven pages, which is still too long. STUDENT: Yes, that is true. It is still seven pages. I wrote a very long introduction to explain the history of urban beekeeping, and that section alone took three pages. I thought it was important to give all that background. PROFESSOR: I understand. Background history is interesting, but for a short proposal, you only need a brief summary. First, you should focus on your specific research question. Next, you need to explain your methods. My advice is to cut your introduction down to just one page. That will instantly save you two pages and bring you to the limit. STUDENT: Oh, that makes a lot of sense. If I shorten the introduction to one page, the rest of my paper will fit perfectly. I want to make sure I get it right. Can I still email you the new version before the final deadline on Friday? PROFESSOR: Yes, absolutely. Please email it to me by Thursday morning. That way, I will have time to look at it and give you some quick feedback before you submit the final version on Friday afternoon. STUDENT: That is perfect. I will work on shortening the introduction tonight and send it to you tomorrow. Thank you so much for your help! [Q1] Why does the student go to see the professor?

  1. Question 2

    According to the professor, what is true about the bibliography?

    • AIt must be exactly three pages long.
    • BIt is not included in the five-page limit.
    • CIt must be emailed to the professor on Thursday.
    • DIt should only focus on urban beekeeping history.
    Show transcript

    (Shared with Q1.) [Q2] According to the professor, what is true about the bibliography?

  1. Question 3

    What does the professor advise the student to do with her introduction?

    • ARemove the section about her research methods.
    • BMove the background history to the bibliography.
    • CReduce its length to a single page.
    • DExpand it to explain more background history.
    Show transcript

    (Shared with Q1.) [Q3] What does the professor advise the student to do with her introduction?

  1. Question 4

    What can be inferred about the student's research proposal?

    • AIt will be graded primarily on the quality of its bibliography.
    • BIt will be accepted even if it is seven pages long.
    • CThe student needs to find a new topic before Thursday morning.
    • DThe main focus should be on the research question and methods.
    Show transcript

    (Shared with Q1.) [Q4] What can be inferred about the student's research proposal?

  1. Question 5

    Why does the professor say this:

    • ATo encourage the student before addressing her concerns.
    • BTo suggest that the student needs to find more sources.
    • CTo explain why the paper is currently too long.
    • DTo ask the student to explain her research methods.
    Show transcript

    (Shared with Q1.) [Replay: "Yes, I read your draft proposal, and your topic on urban bees is excellent."] [Q5] Why does the professor say this:

Lecture 1

  1. Question 6

    What is the lecture mainly about?

    • AMechanisms and ecological roles of kin recognition in plants.
    • BThe competitive advantages of sea rocket plants in crowded beach environments.
    • CHow fungal networks trade soil nutrients for plant sugars in forests.
    • DThe evolutionary reasons why animals and plants developed identical communication systems.
    Show transcript

    NARRATOR: Listen to part of a lecture in a biology class. PROFESSOR: Yesterday we discussed how animals use scent or calls to recognize their relatives. Today, we're shifting our focus to the plant kingdom. It might sound surprising, but plants also exhibit what we call kin recognition. This is the ability of an organism to distinguish between close genetic relatives and unrelated individuals of the same species. For a long time, scientists thought plants just competed blindly with any neighbor for resources like water and light. But recent studies show they can actually identify their siblings—seeds from the same mother plant—and act cooperatively. Now, how do they do this without eyes or ears? The answer lies underground, primarily through root exudates. Root exudates are chemical compounds—like sugars, amino acids, and other metabolites—that roots secrete into the surrounding soil. Think of these exudates as a chemical signature, unique to each plant's genetic makeup. Yes, Lukas? STUDENT: So, if a plant detects a sibling's chemical signature, how does it react? Does it stop growing? PROFESSOR: Not exactly. Instead of stopping growth entirely, it modifies its resource allocation. In a famous experiment with a beach plant called the sea rocket, when plants were potted with strangers, they aggressively grew more roots to compete for nutrients. But when potted with siblings, they restricted their root growth. They, uh, they shared the space rather than trying to crowd each other out. But it gets even more sophisticated in forest ecosystems, thanks to common mycorrhizal networks, or CMNs. CMNs are underground webs of fungal threads that physically connect the root systems of multiple plants. These fungi trade soil nutrients for plant sugars. But here's the fascinating part: older 'mother trees' use these fungal networks to recognize and support their own offspring. In Douglas fir forests, researchers tracked isotopes and found that mature trees preferentially channel carbon and defense signals through the CMN to seedlings that are their direct kin, while offering far less support to unrelated seedlings of the exact same species. Now, some skeptics might say, 'Well, maybe the fungi are choosing where to send the nutrients, not the trees.' And that's a fair point. But experiments where fungal variables were controlled still showed that the mother tree actively regulates its resource distribution based on genetic relatedness. This challenges our traditional view of forests as purely competitive battlegrounds. Instead, they operate more like complex, cooperative family networks. [Q6] What is the lecture mainly about?

  1. Question 7

    According to the professor, what are root exudates?

    • AFungal threads that link different plant species underground.
    • BChemical compounds released by roots that carry a plant's genetic signature.
    • CNutrients that seedlings send back to mature mother trees.
    • DPoisons used by plants to eliminate competing species from the rhizosphere.
    Show transcript

    (Shared with Q6.) [Q7] According to the professor, what are root exudates?

  1. Question 8 (choose all that apply)

    According to the lecture, in what ways do mature Douglas fir trees cooperate with their kin? Choose 2 answers.

    • AThey absorb excess water from the seedlings' roots during dry periods.
    • BThey preferentially channel carbon to related seedlings.
    • CThey transmit defense signals to their offspring through fungal webs.
    • DThey prevent fungal networks from connecting with unrelated species.
    Show transcript

    (Shared with Q6.) [Q8] According to the lecture, in what ways do mature Douglas fir trees cooperate with their kin? Choose 2 answers.

  1. Question 9

    Why does the professor mention the perspective of skeptics regarding fungal networks?

    • ATo argue that mycorrhizal networks are less cooperative than previously assumed.
    • BTo highlight a major flaw in the experimental design of the Douglas fir study.
    • CTo introduce evidence that confirms the active role of plants in resource distribution.
    • DTo suggest that fungi and plants are constantly competing for carbon.
    Show transcript

    (Shared with Q6.) [Q9] Why does the professor mention the perspective of skeptics regarding fungal networks?

  1. Question 10

    What did researchers observe when sea rocket plants were potted with unrelated plants?

    • AThey released chemical compounds that stunted the strangers' growth.
    • BThey relied on mycorrhizal networks to share scarce water.
    • CThey stopped photosynthetic activity to conserve energy.
    • DThey grew more roots to compete more aggressively for resources.
    Show transcript

    (Shared with Q6.) [Q10] What did researchers observe when sea rocket plants were potted with unrelated plants?

  1. Question 11

    Why does the speaker say this:

    • ATo describe the cooperative outcome of restricted root growth in sibling plants.
    • BTo correct a previous statement about the speed of plant root development.
    • CTo express skepticism about whether plants can actually share resources.
    • DTo explain why beach plants are unable to survive in crowded environments.
    Show transcript

    (Shared with Q6.) [Replay: "They, uh, they shared the space rather than trying to crowd each other out."] [Q11] Why does the speaker say this:

Conversation 2

  1. Question 12

    Why does the student go to see the registrar's office administrator?

    • ATo resolve an issue regarding her graduation credit count
    • BTo appeal a grade she received for a summer internship
    • CTo request an extension for a course registration deadline
    • DTo submit a petition to change her major to environmental science
    Show transcript

    NARRATOR: Listen to a conversation between a student and a registrar's office administrator. STUDENT: Hi there. I'm hoping you can help me with my graduation audit. I received an email saying I'm three credits short of the requirement for my bachelor's degree in environmental science, but... well, I'm pretty sure I have enough. STAFF: Hello. Let's take a look. What is your student ID number? ... Okay, Sofia. I see your record here. According to the system, you have 117 completed credits, and you need 120 to graduate. Are you currently enrolled in any other classes? STUDENT: Yes, I'm taking 15 credits this semester, which should bring me to, uh, wait, 132 total. But the audit says I only have 117 completed, which doesn't include the internship I did last summer. That was supposed to be worth three credits. STAFF: Ah, the summer internship. Did you register that with the department before you started? STUDENT: Yes, I did. My advisor, Professor Evans, approved it. I have the signed approval form right here, actually. STAFF: Okay, that's the pre-approval. But to actually get those credits on your transcript, you needed to submit a completed Internship Credit Validation Form—that's Form 402—along with a brief evaluation from your internship supervisor. Our deadline for submitting summer credit validation forms was October 15th. Today is, let's see, November 10th. So that's why it's not showing up. STUDENT: Oh, no. I thought... I thought Professor Evans would submit it directly to you once I emailed her my supervisor's evaluation. I didn't realize I had to submit a separate form myself. Is it too late to get those credits? I really need them to graduate in the spring. STAFF: Don't worry, it's not impossible to fix. You can still submit the form late, but you'll have to file a late-submission petition. It requires a signature from your department chair—not just your advisor—and there is a forty-five dollar late fee. STUDENT: Forty-five dollars? That's... well, I guess I don't have much of a choice. How long does the petition take to process? STAFF: Usually about two weeks once we receive all the paperwork and the payment. Since your graduation isn't until the end of the spring term, we have plenty of time. But I'd recommend getting that department chair's signature as soon as possible, because they can be hard to track down during midterms. STUDENT: Right, Dr. Ramirez is usually very busy. I'll head over to her office right now to see if she's in. Where do I get Form 402 and the petition form? STAFF: You can download both of them from our office website under the 'Student Forms' tab. Just print them out, get the signature, and bring them back here with the payment. We accept cards or student account billing. STUDENT: Great. Thank you so much for clarifying this. I was really panicking. STAFF: You're welcome. We'll get it sorted out. [Q12] Why does the student go to see the registrar's office administrator?

  1. Question 13

    According to the administrator, why are the student's internship credits missing from her audit?

    • AHer academic advisor did not approve the internship in advance.
    • BShe did not submit the required validation form by the deadline.
    • CHer internship supervisor failed to write an evaluation.
    • DThe registrar's office lost her original paperwork.
    Show transcript

    (Shared with Q12.) [Q13] According to the administrator, why are the student's internship credits missing from her audit?

  1. Question 14

    What can be inferred about the department chair, Dr. Ramirez?

    • AShe is unlikely to approve the student's late-submission petition.
    • BShe has the authority to waive the forty-five dollar late fee.
    • CShe may be difficult to meet with during the current academic period.
    • DShe was responsible for submitting the validation form on behalf of the student.
    Show transcript

    (Shared with Q12.) [Q14] What can be inferred about the department chair, Dr. Ramirez?

  1. Question 15

    Why does the administrator mention October 15th?

    • ATo point out the date when the student's graduation audit was generated
    • BTo warn the student about an upcoming deadline for spring course registration
    • CTo clarify when the student's summer internship actually ended
    • DTo establish the deadline by which internship credits had to be validated
    Show transcript

    (Shared with Q12.) [Q15] Why does the administrator mention October 15th?

  1. Question 16

    Why does the student say this:

    • ATo express her frustration about a fee she must pay
    • BTo question the registrar's official policy regarding late submissions
    • CTo complain that she cannot afford the required fee
    • DTo suggest that the fee amount is unfair compared to other universities
    Show transcript

    (Shared with Q12.) [Replay: "Forty-five dollars? That's... well, I guess I don't have much of a choice."] [Q16] Why does the student say this:

Lecture 2

  1. Question 17

    What is the lecture mainly about?

    • AThe atmospheric conditions and physical processes that trigger cryoseisms.
    • BThe geological differences between tectonic earthquakes and volcanic tremors.
    • CMethods used by geophysicists to measure rapid soil temperature fluctuations.
    • DThe historical impact of the polar vortex on agricultural soil erosion.
    Show transcript

    NARRATOR: Listen to part of a lecture in a geophysics class. PROFESSOR: Today, we're venturing into a branch of geophysics that bridges meteorology and seismology, focusing on a phenomenon known as a cryoseism—often colloquially referred to as a frost quake. Now, unlike tectonic earthquakes, which are driven by the movement of tectonic plates deep within the Earth's crust, a cryoseism is a non-tectonic seismic event. It's caused by a sudden, rapid freezing of water-saturated soil or rock. When temperatures plummet rapidly, the water trapped underground freezes. And as we know, water expands when it freezes, which exerts immense hydrostatic pressure on the surrounding frozen ground. When this pressure exceeds the shear strength of the soil or rock, it ruptures violently, producing loud booming sounds and localized ground shaking. STUDENT: So, um, does this happen every winter in cold climates, or does it require very specific conditions? PROFESSOR: An excellent question, Aisha. It actually requires a highly precise sequence of meteorological events. First, you need a lack of significant snow cover. Why? Because snow acts as an insulating blanket. If there's a thick layer of snow, it insulates the soil, keeping it at a relatively stable temperature and preventing the rapid deep freeze needed. Second, you need saturated soil—usually from a recent rainstorm or rapid snowmelt—followed immediately by what we call thermal contraction cracking. This is a process where a sudden, extreme drop in temperature—say, a plunge of thirty degrees Celsius within a single day—causes the top layer of soil to rapidly contract and split. This split allows water to seep deeper and freeze almost instantaneously. PROFESSOR: To illustrate this, let's look at a well-documented case from early 2014 in the Great Lakes region. In January of that year, a sudden shift in the polar vortex brought unprecedented arctic air to areas that had just experienced unseasonably warm rain. The ground was completely saturated, and there was virtually no snow cover to protect it. Within twelve hours, temperatures dropped from above freezing to nearly minus twenty-five degrees—uh, actually, it was minus twenty-eight degrees, but the point is the extreme drop. Residents reported hearing loud, explosive booms—some even thought trees were falling on their roofs or that gas lines were exploding. Seismologists analyzed the data and found that these events had incredibly shallow focal depths—literally within the top few meters of the soil. This extremely shallow depth is a key distinguishing feature of cryoseisms. PROFESSOR: Another related concept here is cryoseismic frost-heaving, which is the localized upward displacement of soil that occurs during these rapid freeze-thaw cycles. In the 2014 event, this heaving actually cracked driveways and displaced road signs. Now, because these events are so localized and shallow, their seismic waves decay very quickly. This means while someone standing a hundred meters away might feel a violent jolt and hear a deafening bang, a standard seismic station ten kilometers away might barely register it. And that, of course, presents a major challenge for geophysicists trying to map these occurrences. They have to rely heavily on citizen science—on-the-ground reports from the public—to supplement their instrument data. [Q17] What is the lecture mainly about?

  1. Question 18

    According to the professor, why does a thick layer of snow prevent cryoseisms from occurring?

    • AIt prevents liquid water from saturating the underlying soil.
    • BIt insulates the ground against sudden, extreme temperature drops.
    • CIt absorbs the seismic energy generated by cracking bedrock.
    • DIt increases the shear strength of the surface soil layers.
    Show transcript

    (Shared with Q17.) [Q18] According to the professor, why does a thick layer of snow prevent cryoseisms from occurring?

  1. Question 19

    Why does the professor mention the sound of falling trees and exploding gas lines reported during the 2014 event?

    • ATo explain why seismologists initially misclassified the event as a tectonic earthquake.
    • BTo provide evidence that the 2014 event was exceptionally destructive compared to typical frost quakes.
    • CTo illustrate how the sounds produced by cryoseisms are commonly misattributed to other sources.
    • DTo emphasize the extreme intensity of the acoustic energy generated by thermal contraction.
    Show transcript

    (Shared with Q17.) [Q19] Why does the professor mention the sound of falling trees and exploding gas lines reported during the 2014 event?

  1. Question 20

    What is the relationship between thermal contraction cracking and cryoseismic frost-heaving?

    • AThermal contraction cracking only occurs after frost-heaving has weakened the structural integrity of the bedrock.
    • BBoth processes are initiated by an increase in tectonic stress, but they affect different depths of the Earth's crust.
    • CFrost-heaving prevents thermal contraction cracking by releasing the hydrostatic pressure built up in the soil.
    • DThermal contraction cracking creates pathways for water to enter, while frost-heaving is the resulting upward swelling as that water freezes.
    Show transcript

    (Shared with Q17.) [Q20] What is the relationship between thermal contraction cracking and cryoseismic frost-heaving?

  1. Question 21

    What can be inferred about the seismic data recorded during a cryoseism?

    • AIt may go undetected by standard monitoring stations if the event occurs far away.
    • BIt is usually indistinguishable from the data of deep-focus tectonic earthquakes.
    • CIt is highly effective at predicting when subsequent frost-heaving will occur.
    • DIt shows that cryoseisms generate waves that travel much faster than typical seismic waves.
    Show transcript

    (Shared with Q17.) [Q21] What can be inferred about the seismic data recorded during a cryoseism?

  1. Question 22

    Why does the speaker say this:

    • ATo suggest that current seismic mapping software is outdated.
    • BTo explain why geophysicists must gather observational reports from local residents.
    • CTo argue that financial resources should be redirected to monitoring tectonic faults instead.
    • DTo criticize the lack of scientific interest in non-tectonic seismic events.
    Show transcript

    (Shared with Q17.) [Replay: "And that, of course, presents a major challenge for geophysicists trying to map these occurrences."] [Q22] Why does the speaker say this:

Lecture 3

  1. Question 23

    What is the lecture mainly about?

    • AHow the human brain interprets and reconstructs silent intervals in spoken language
    • BWhy historical linguistic studies failed to account for acoustic occlusion
    • CThe acoustic differences between voiced and voiceless plosive consonants
    • DMethods used by cognitive psychologists to eliminate background noise in communication
    Show transcript

    NARRATOR: Listen to part of a lecture in a linguistics class. PROFESSOR: Today, we are going to explore a rather counterintuitive aspect of psycholinguistics—specifically, how we perceive silence in spoken language. When you listen to someone speak, you probably feel like you're hearing a continuous, unbroken stream of sounds, occasionally punctuated by pauses between words. But acoustic measurements show that natural speech is actually riddled with tiny silences. PROFESSOR: Take, for instance, what linguists call stop gaps. A stop gap is a brief period of absolute silence—often lasting just a few milliseconds—that occurs right before we articulate voiceless plosive consonants, like the sound of 'p', 't', or 'k'. During a stop gap, your vocal tract completely blocks the airflow to build up pressure. Now, your brain doesn't register this silence as an empty void in the conversation. Instead, it interprets this micro-pause as a structural cue, recognizing it as the silent preparation phase of the upcoming consonant. If we artificially erase this tiny silence from a recording of the word 'split,' listeners will actually hear the word 'slit' instead. The silence is, quite literally, perceived as part of the consonant itself. PROFESSOR: Now, this brings us to an even more fascinating phenomenon: how our cognitive system actively manages external interruptions in speech. When a sound is completely obliterated by a loud noise, say, a door slamming, we don't just lose that part of the message. Our brain often restores it. This is known as the phonemic restoration effect, where listeners hear a missing speech sound as if it were actually present, provided it is replaced by a louder, non-speech sound like a cough or static. PROFESSOR: But here is the catch. This restoration only occurs if the missing segment is replaced by another sound. If we replace that same speech sound with absolute silence—with a literal gap in the acoustic signal—our brain fails to fill it in. We clearly hear the gap, and the word sounds fractured. Why does this happen? Well, it relates to what cognitive psychologists call acoustic occlusion. This is the perceptual assumption that a louder background sound is merely blocking, or occluding, a continuous underlying signal, rather than the signal itself having stopped. Our auditory system operates on a sort of continuity rule. If there's a loud noise, the brain assumes the speech signal is still there behind the noise, so it reconstructs the missing phonemes using contextual clues. But if there is pure silence during that gap, the brain has no acoustic excuse, so to speak, to assume the signal continued. It knows the speaker actually stopped producing sound. Yes, Aisha? STUDENT: So, wait... does this mean our brain is actually generating the acoustic frequency of the missing sound? Like, do our ears physically process it, or is it purely a mental projection? PROFESSOR: That's an excellent question, Aisha. Neurological studies suggest that the auditory cortex—the part of the brain that processes sound—actually fires in a way that closely mirrors the missing sound. It's not just a cognitive guess or a logical deduction after the fact; the brain genuinely reconstructs the sensory experience of the sound. It literally hears the missing consonant. PROFESSOR: Let's look at a classic experiment conducted by Richard Warren in 1970. He presented participants with a recorded sentence: 'The state governors met with their respective legislatures.' However, he deleted the 's' sound... uh, actually, the first 's' in 'legislatures'... and replaced it with a brief cough. Remarkably, nearly all participants reported hearing the complete word 'legislatures' and couldn't even pinpoint where the cough had occurred. But when the cough was removed and replaced with a silent gap of the exact same duration... well, the illusion vanished. The participants easily identified the gap and struggled to comprehend the word. This shows how crucial that masking sound is. Without it, our brains can't apply the continuity rule, leaving us with a fragmented stream of speech. [Q23] What is the lecture mainly about?

  1. Question 24

    According to the professor, what happens when the silent "stop gap" is artificially removed from a recording of the word "split"?

    • AThe voiceless plosive consonant is perceived as being much louder
    • BListeners perceive a completely different word
    • CThe word sounds highly unnatural but remains recognizable
    • DListeners believe they hear a door slamming or a cough
    Show transcript

    (Shared with Q23.) [Q24] According to the professor, what happens when the silent "stop gap" is artificially removed from a recording of the word "split"?

  1. Question 25 (choose all that apply)

    According to the professor, what conditions must be met for the phonemic restoration effect to occur? Choose 2 answers.

    • AThe missing speech sound must be replaced by a louder, non-speech noise.
    • BThe silent pause must occur directly before a voiceless plosive consonant.
    • CThe brain must have contextual clues to help reconstruct the missing sound.
    • DThe speaker must speak at a slower, more deliberate pace.
    Show transcript

    (Shared with Q23.) [Q25] According to the professor, what conditions must be met for the phonemic restoration effect to occur? Choose 2 answers.

  1. Question 26

    Why does the professor discuss the "continuity rule" used by our auditory system?

    • ATo challenge Richard Warren's conclusions regarding phonemic restoration
    • BTo illustrate how listeners distinguish between different types of plosive consonants
    • CTo explain the cognitive mechanism behind the brain's reconstruction of masked sounds
    • DTo argue that absolute silence is necessary for speech comprehension
    Show transcript

    (Shared with Q23.) [Q26] Why does the professor discuss the "continuity rule" used by our auditory system?

  1. Question 27

    What does the professor imply about the brain's reconstruction of missing speech sounds during phonemic restoration?

    • AIt occurs more frequently in people with professional linguistic training
    • BIt is limited to very simple words with few syllables
    • CIt prevents listeners from understanding the overall meaning of a sentence
    • DIt is an actual sensory reconstruction rather than just a logical guess
    Show transcript

    (Shared with Q23.) [Q27] What does the professor imply about the brain's reconstruction of missing speech sounds during phonemic restoration?

  1. Question 28

    Why does the speaker say this:

    • ATo clarify why absolute silence prevents the brain from filling in missing speech
    • BTo point out a flaw in the design of early acoustic experiments
    • CTo suggest that the brain actively ignores silence to save cognitive energy
    • DTo criticize speakers who pause too frequently during natural conversation
    Show transcript

    (Shared with Q23.) [Replay: "But if there is pure silence during that gap, the brain has no acoustic excuse, so to speak, to assume the signal continued."] [Q28] Why does the speaker say this:

More papers like this