영어 모의고사 (자동 편성)

For centuries, dreams have fascinated scientists and philosophers alike, yet no single theory fully ①explains why the sleeping brain generates such vivid and often bizarre experiences. One prominent idea suggests that dreaming helps the brain process emotional experiences, ②replays difficult events in a safe, low-stakes environment so that their emotional intensity gradually fades. Another theory proposes that dreams serve a more practical function, ③allowing the brain to rehearse responses to threats without any real danger. Still other researchers argue that dreaming is simply a byproduct of the brain organizing memories, with vivid imagery ④arising as the mind sorts through the day's information rather than serving any independent purpose of its own. Because these theories rest on indirect evidence, none has ⑤been conclusively proven.

Open a music streaming app on any given morning, and a personalized playlist is usually already waiting, ①assembled overnight from songs the algorithm predicts will match a listener's current mood. This prediction relies on far more than genre alone; the system studies skip rates, replay counts, and even the time of day a song is typically ②playing, building a remarkably detailed profile of individual taste. Listeners often praise the feature for ③introducing them to artists they never would have searched for on their own, effectively acting as a tireless music scout working around the clock. Musicians, meanwhile, have mixed feelings about this shift in how audiences ④discover new music. A song that the algorithm decides not to promote may struggle ⑤to reach listeners no matter how well it was written.

Many companies today advertise their products as environmentally friendly, yet not all of these claims are ①accurate. Consumers, who are increasingly ②concerned about climate change, often trust such claims without questioning them closely. As a result, they may pay ③higher prices for products that are no more sustainable than ordinary alternatives. Genuine environmental efforts, which usually require significant investment and long-term planning, are far more ④costly than simply changing a label. Therefore, governments should establish clear standards that require companies to prove their environmental claims with ⑤unverifiable data.

VO2 max, defined as the maximum volume of oxygen a person's body can consume and use during intense exercise, is widely regarded as one of the best single indicators of cardiorespiratory fitness. Elite endurance athletes typically post VO2 max values far ①higher than those of untrained individuals, reflecting hearts that pump larger volumes of blood and muscles that extract oxygen from that blood with remarkable efficiency. While genetics accounts for a substantial portion of an individual's potential VO2 max, consistent aerobic training can still ②raise the measurement considerably over months of dedicated effort. Interval training, which alternates short bursts of near-maximal effort with periods of recovery, has proven particularly ③effective at improving this measurement compared to steady, moderate-intensity exercise alone. It is worth noting, however, that a high VO2 max does not guarantee success in competition, since factors such as running economy, pacing strategy, and mental resilience also play a ④decisive role in determining who actually crosses the finish line first. These additional factors remain ⑤irrelevant to overall performance.

Wearable devices that track sleep have become ①enormously 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 ②indirect approach, however, introduces ③significant 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 ④narrowly between brands. Despite these limitations, many users have come to treat the nightly score generated by their device as an ⑤objective medical verdict, sometimes experiencing anxiety when the number falls below what they expect, a phenomenon researchers have begun calling orthosomnia.

When people consistently sleep too little, the body's hormonal balance shifts in ways that can quietly encourage weight gain. Two hormones in particular play opposing roles in regulating appetite: leptin signals fullness to the brain, while ghrelin stimulates the sensation of hunger. Studies show that sleep deprivation lowers leptin levels while raising ghrelin levels, so _______________, even after a normal-sized meal. At the same time, insufficient sleep interferes with how efficiently the body processes glucose, making cells less responsive to insulin and leaving more sugar circulating in the bloodstream than usual. Over months or years, this combination of increased appetite and reduced insulin sensitivity can contribute to steady weight gain and raise the risk of developing type 2 diabetes. Because these effects build up so gradually, many people never connect their shifting eating habits or worsening blood sugar to something as ordinary as a few lost hours of sleep each night.

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.

Adaptive learning apps promise something no traditional classroom can easily offer: a lesson plan that adjusts itself to each individual student in real time. (A) As a student answers practice questions, the app tracks which concepts are mastered and which remain shaky, then quietly reshuffles the next set of problems to target the weaker areas. (B) Early studies suggest that this personalized pacing can help struggling students catch up faster than a one-size-fits-all worksheet ever could. (C) However, critics caution that an app cannot replace the encouragement, humor, and flexibility a human teacher brings to a lesson.

In short, an effective fueling plan treats carbohydrate loading as one tool among many, not a substitute for well-rounded nutrition. In the days leading up to an endurance event, many athletes deliberately increase their carbohydrate intake while reducing training volume, a practice known as carbohydrate loading. ( ① ) The strategy is designed to maximize the amount of glycogen, the storage form of carbohydrate, packed into muscle tissue before competition begins. ( ② ) Because glycogen serves as the primary fuel source during prolonged, intense exercise, entering an event with fuller stores can delay the point of exhaustion that runners often call hitting the wall. ( ③ ) Sports nutritionists caution, however, that the timing and composition of meals matter as much as the total quantity of carbohydrate consumed, since eating unfamiliar foods immediately before competition can cause digestive discomfort. Athletes are therefore advised to practice their nutrition strategy during training rather than experimenting with it for the first time on race day. ( ④ ) Beyond carbohydrates, adequate protein and micronutrient intake throughout the training cycle remains essential, since fueling strategy is only one part of a much larger nutritional picture. ( ⑤ )

주어진 문장: A color considered lucky and celebratory in one culture, for instance, might represent grief in another. Color plays a surprisingly powerful role in how consumers perceive brands, often shaping first impressions before a single word is read. ( ① ) Studies suggest that people form judgments about a product within seconds of seeing its packaging, and color accounts for a significant portion of that instant reaction. ( ② ) Blue, for instance, is frequently used by financial and technology companies because it tends to evoke feelings of trust and stability. ( ③ ) Red, in contrast, is associated with energy and urgency, which explains why it appears so often in logos for fast-food chains and clearance sales. ( ④ ) Despite these general patterns, cultural context matters significantly. ( ⑤ ) Marketers who ignore these cultural differences risk sending unintended messages to international audiences.