영어 모의고사 (자동 편성)

Across the world, teenagers are chronically short on sleep, often getting two or three hours less than the eight to ten hours experts recommend for their age. Part of the problem lies in biology: as puberty begins, the body's internal clock naturally shifts later, ① making it difficult for teenagers to fall asleep before eleven at night. Yet school start times rarely adjust to this shift, ② forcing students to wake before their bodies are ready. The consequences extend well beyond simple tiredness. Chronic sleep loss during adolescence has been linked to impaired concentration, weakened memory, and a higher risk of anxiety and depression. It can also disrupt the hormones ③ that regulating appetite, contributing to unhealthy weight gain over time. Some school districts have experimented with ④ delaying start times by even thirty minutes, and early results suggest that students who gain that extra rest show improved grades, better mood, and fewer tardy arrivals. Despite this evidence, changing entrenched school schedules ⑤ remains a slow and contentious process.

Carbon neutrality refers to a state in which the amount of greenhouse gases a country or company releases into the atmosphere is ①<u>balanced</u> by the amount it removes, resulting in zero net emissions. Achieving this goal typically requires several sequential stages rather than a single sudden action. First, organizations attempt to ②<u>reduce</u> emissions directly by replacing fossil fuels with renewable energy sources such as solar or wind power. Next, they ③<u>improve</u> efficiency throughout their operations, minimizing the energy wasted during production and transportation. Only after these direct measures have been ④<u>maximized</u> do most organizations turn to offsetting, which involves funding projects like reforestation or carbon capture to compensate for emissions that cannot yet be eliminated. Critics argue, however, that some companies exploit offsetting too early, using it to avoid making genuine reductions. Therefore, experts insist that a ⑤<u>flawed</u> roadmap must always prioritize actual emission cuts before relying on compensation.

Wearable devices that track sleep have become ① enormously popular, promising a detailed breakdown of light, deep, and REM sleep each night. These gadgets typically rely on movement sensors and heart rate monitors to estimate sleep stages, since directly measuring brain activity would require equipment found only in a sleep laboratory. This ② indirect approach, however, introduces ③ significant uncertainty. Independent studies comparing wearable data with polysomnography, the gold-standard method used in clinical sleep labs, have found that consumer devices are reasonably accurate at distinguishing sleep from wakefulness but considerably less reliable at identifying specific sleep stages. Some trackers overestimate deep sleep, while others underestimate the amount of time spent in REM sleep, and the margin of error can vary ④ narrowly between brands. Despite these limitations, many users have come to treat the nightly score generated by their device as an ⑤ objective medical verdict, sometimes experiencing anxiety when the number falls below what they expect, a phenomenon researchers have begun calling orthosomnia.

Every cell in the human body follows an internal timer known as the circadian rhythm, a roughly twenty-four-hour cycle that ① governs when we feel alert and when we feel drowsy. This clock is regulated primarily by a tiny cluster of neurons in the brain that responds to light entering through the eyes. When morning sunlight strikes the retina, the cluster signals the body to ② suppress sleep hormones and raise body temperature, preparing us for activity. As evening approaches and light fades, the same mechanism triggers the release of melatonin, a hormone that ③ promotes drowsiness. Because this rhythm evolved around the natural cycle of day and night, modern habits such as staying indoors under artificial light or working night shifts can push the internal clock ④ out of sync with the external environment. Such misalignment does not simply cause tiredness; it has also been associated with digestive problems and ⑤ heightened concentration, suggesting that timing matters as much as total sleep hours.

Climate scientists frequently warn about tipping points, _______________. Unlike gradual warming, which unfolds steadily over decades, crossing a tipping point can produce dramatic consequences within a short period. For instance, as Arctic ice melts, it exposes darker ocean water that absorbs more sunlight than reflective ice, accelerating further melting in a self-reinforcing cycle. Similarly, scientists worry that a major ocean current, which currently redistributes heat across the planet, could slow dramatically if enough freshwater from melting glaciers dilutes the surrounding seawater. Once such thresholds are crossed, restoring the original balance may become nearly impossible, even if emissions are later reduced. Therefore, researchers argue that preventing these transitions matters more than merely slowing average temperature increases. Identifying how close each system stands to its threshold remains one of the most urgent challenges in climate research.

Anyone who has ridden a bicycle after a decade away from one has likely experienced muscle memory firsthand: the body seems to recall a complex skill almost instantly, even when conscious memory of the exact movements has faded. Contrary to what the name suggests, muscles themselves do not actually store memories; the phenomenon originates in the brain and nervous system, where repeated practice gradually shifts control of a well-learned movement from regions associated with conscious thought to areas that operate largely automatically. This shift explains why a skilled athlete can execute a complicated sequence of movements without consciously thinking through each individual step, freeing mental attention for strategy and decision-making instead. Interestingly, research also suggests that _______________.

For decades, athletes were taught to stretch a muscle and hold the position before any competition, believing that this practice alone would prevent injury. (A) Recent research, however, has complicated that assumption, since static stretching can actually reduce a muscle's ability to generate explosive force immediately afterward. (B) Dynamic stretching, by contrast, involves controlled, repeated movement through a joint's full range of motion and appears to prepare muscles for activity without this weakening effect. (C) As a result, many coaches now recommend saving static stretching for after a workout while reserving dynamic movements for the warm-up period before intense effort begins.

As climate change accelerates, investors around the world are paying closer attention to how companies affect the environment and society. (A) Recently, however, many corporations have learned to boost their ESG scores without genuinely transforming their operations. Some firms publish glossy reports filled with impressive statistics while their actual carbon emissions barely decline, exploiting the fact that ESG evaluation systems still lack consistent global standards. (B) ESG management refers to a company's efforts to consider Environmental, Social, and Governance factors alongside profit when making business decisions. Investors increasingly rely on ESG ratings to judge whether a company is managed responsibly and sustainably over the long term. (C) This gap between appearance and substance has led critics to demand stricter, more transparent criteria for measuring corporate responsibility. Genuine ESG management, in contrast, requires measurable targets, independent audits, and long-term accountability rather than one-time donations or attractive slogans. Investors who wish to identify truly responsible companies should therefore examine detailed disclosures instead of trusting labels alone.

Treating only one side of this equation, therefore, often leaves the other free to sustain the sleeplessness on its own. Insomnia is rarely 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. ( ① ) 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. ( ② ) At the same time, the body's stress response system can become chronically activated, releasing hormones such as cortisol that keep heart rate and body temperature elevated at night, both of which interfere with the natural drop in arousal needed to fall asleep. ( ③ ) Poor sleep habits, including irregular bedtimes and excessive screen use before bed, can further weaken the body's internal signals for sleep onset. ( ④ ) Because these psychological and physiological factors reinforce 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. ( ⑤ )

In other words, sleep does not simply preserve what was learned but actively works to make sense of it. During sleep, the brain does not simply rest; it actively reorganizes the day's experiences into lasting memories through a process called consolidation. ( ① ) Newly formed memories are initially fragile and stored primarily in a brain region called the hippocampus, which has limited long-term capacity. ( ② ) While a person sleeps, particularly during the deep stages of non-REM sleep, neural activity replays these fresh memory traces in rapid, compressed sequences, gradually transferring the information to the cortex for more durable, long-term storage. This replay strengthens the connections between neurons that encoded the original experience, making the memory more resistant to interference from unrelated events the following day. ( ③ ) Sleep researchers have demonstrated this effect experimentally: participants who slept after learning a list of word pairs recalled more items the next day than participants who remained awake instead. ( ④ ) Crucially, the benefit was not limited to simple recall; sleep also seemed to help participants extract general patterns from the material, suggesting that consolidation involves more than passive storage. ( ⑤ )