영어 모의고사 (자동 편성)

Melatonin is a hormone ①produced by a small gland deep within the brain, and its release follows a remarkably predictable daily pattern. Levels stay low throughout the bright hours of the day, ②begin rising in the evening as darkness falls, peak in the middle of the night, and then decline again as morning approaches. This rhythm is controlled primarily by light: specialized cells in the eye detect brightness and send signals that either permit or ③suppress melatonin production, which is why exposure to bright screens late at night can delay its release and make falling asleep more difficult. Unlike some hormones that directly cause the body to perform a task, melatonin does not force sleep to occur; instead, it signals to the rest of the body that night has arrived, ④preparing various systems to shift into a lower-energy state. Because of this signaling role, taking melatonin supplements at the wrong time can shift a person's internal clock in the opposite direction from what was ⑤intending.

Insomnia is ①rarely caused by a single factor; it usually emerges from an interaction between psychological stress and physiological arousal that keeps the body from settling into sleep. A common trigger is what researchers call cognitive hyperarousal, in which the mind continues to race with worries about work, relationships, or even the inability to sleep itself, creating a frustrating cycle where anxiety about insomnia becomes a cause of insomnia. At the same time, the body's stress response system can become ②chronically activated, releasing hormones such as cortisol that keep heart rate and body temperature ③depressed at night, both of which interfere with the natural drop in arousal needed to fall asleep. Poor sleep habits, including irregular bedtimes and excessive screen use before bed, can further ④weaken the body's internal signals for sleep onset. Because these psychological and physiological factors ⑤reinforce one another, effective treatment for chronic insomnia addresses both the racing mind and the underlying pattern of physical tension, rather than relying on medication alone.

Across many countries, high schools begin classes ①early in the morning, often before eight o'clock. This schedule assumes that teenagers can simply go to bed earlier to compensate, but biology tells a different story. During adolescence, the body's internal clock shifts ②earlier, delaying the release of melatonin until well after ten at night. As a result, most teenagers are not physiologically ready to fall asleep until much later than younger children or adults. When early start times force them to wake before their bodies have completed a full sleep cycle, the mismatch ③accumulates into a chronic sleep debt that affects concentration and mood throughout the school day. Researchers who study this mismatch argue that the underlying problem is not laziness or poor discipline among students, but a scheduling system built around adult rhythms rather than ④adolescent ones. Some school districts that delayed their start times by thirty minutes reported ⑤measurable improvements in attendance.

Sleep apnea is a disorder in which breathing repeatedly stops and restarts during sleep, often because the muscles at the back of the throat ①relax too much and block the airway. Each pause can last from a few seconds to over a minute, and it may occur dozens of times in a single night without the sleeper ever ②waking up fully. Because these interruptions rarely produce a clear memory the next morning, many people remain ③unaware that anything is wrong, even as chronic fatigue, headaches, and irritability build up over months. Doctors therefore rely less on a patient's own account of the night and more on ④subjective measurements, such as overnight oxygen levels and airflow patterns recorded in a sleep laboratory. Left untreated, the disorder has been linked to serious long-term risks, including high blood pressure and heart disease, which makes an accurate diagnosis far more ⑤urgent than its subtle nighttime symptoms might suggest.

Smartphones, tablets, and computer screens all emit a significant amount of blue light, a short-wavelength light that our eyes are especially sensitive to. During the day, exposure to blue light from the sun helps keep us alert and mentally sharp, which is generally beneficial. At night, however, the same wavelength can interfere with the body's natural preparation for sleep. Specialized cells in the retina detect blue light and send signals to the brain's internal clock, which results in _______________. Studies have found that people who scroll through their phones in bed before sleeping take longer to fall asleep and experience lighter, more easily disrupted sleep than those who avoid screens. Some devices now offer a night mode that shifts the display toward warmer tones, reducing blue light output in the evening. While this feature may help slightly, sleep researchers generally recommend limiting screen use altogether in the hour before bedtime for the best results.

Only a decade ago, translation apps produced sentences so awkward that users often laughed at the results rather than trusting them. (A) Frequent travelers now point their phone cameras at street signs and receive an instant translation overlaid on the screen, thanks to this leap in accuracy. (B) Even so, the technology still struggles with humor, sarcasm, and cultural nuance, areas where a single wrong word can completely change the intended meaning. (C) Today, many of these apps rely on neural networks that analyze entire sentences at once, capturing context instead of translating word by word.

Travelers who cross several time zones in a single flight often arrive feeling exhausted, foggy, and strangely out of sync with the local clock, a condition widely known as jet lag. (A) The discomfort arises because the body's internal clock, which governs sleep, hunger, and alertness, continues to run on the schedule of the departure city even after landing, and realigning it typically takes about one day for every time zone crossed. (B) Flying eastward tends to produce more severe symptoms than flying westward, because advancing the internal clock forward is generally harder for the body than delaying it. (C) Exposure to natural light at the right moments after arrival can help speed up the adjustment, since light is the strongest external cue the internal clock uses to reset itself.

Climate change is not only a scientific and political issue but also an emotional one for many people today. (A) Teenagers and young adults tend to feel it most intensely, since they expect to live through many more decades of a changing climate than older generations do. (B) This emotional dimension, known as eco-anxiety, refers to persistent worry, grief, or fear that stems from awareness of climate change and its future consequences. (C) Fortunately, channeling this anxiety into constructive action, such as joining community environmental projects, can help restore a sense of control rather than deepen despair.

Imagine two factories making the same product: one in a country with strict carbon rules, and one in a country with almost none. (A) However, critics claim it unfairly burdens developing countries, which often lack money to modernize factories quickly. For example, a small exporter in a poorer nation might struggle to pay the added charge, though it contributes little to global emissions. Still, if wealthier nations pair the policy with technical support, it could become a genuinely fair tool for cutting emissions worldwide. (B) Supporters argue that the system protects domestic industries and pushes foreign manufacturers toward cleaner methods. (C) The factory facing stricter rules often spends more, which can make its goods pricier than those made elsewhere. To fix this imbalance, some governments have introduced the carbon border adjustment mechanism, a policy charging imported goods a fee based on how much carbon was released while producing them.

Climate change deniers often seem to ignore evidence that contradicts their views, and psychologists have a specific explanation for this behavior. (A) For example, someone whose job depends on fossil fuels may search for reasons to doubt the data, even while insisting that they respect science. (B) This concept, called motivated reasoning, describes how people process information in ways that protect their existing beliefs and lifestyles rather than pursue objective truth. (C) Rather than being a simple failure of intelligence, this pattern reflects a well-documented psychological tendency studied for decades.