영어 모의고사 (자동 편성)

Many teenagers check their social media accounts dozens of times a day, worried that they might miss something important happening among their friends. This anxiety, known as FOMO, or the fear of missing out, ①arises when people believe that others are enjoying experiences from which they themselves are excluded. For example, a student ②scrolling through photos of a party she was not invited to may suddenly feel a wave of loneliness and regret, even though the event has already ended. Constantly ③refreshed feeds to avoid missing such updates, however, makes it difficult to concentrate on schoolwork or conversations happening in the present moment. Moreover, this endless comparison with curated highlights of other people's lives tends to ④deepen feelings of anxiety rather than relieve them. Therefore, students should learn ⑤to limit their social media use and focus more attention on the relationships and activities directly in front of them.

Coaches have traditionally focused athlete preparation on training volume and nutrition, but a growing body of research ① suggests that sleep deserves equal attention. During deep sleep, the body releases growth hormone, a substance essential for ② repairing muscle tissue damaged during intense training, while the brain consolidates motor skills practiced earlier that day into more stable, efficient patterns. Athletes who sleep fewer than seven hours a night have been shown ③ suffering more injuries, slower reaction times, and reduced accuracy compared to well-rested peers performing the identical drills. Frequent travel across time zones compounds this challenge considerably, since jet lag can ④ disrupt an athlete's natural sleep-wake cycle for several days after a long flight. In response, many professional teams now employ sleep specialists ⑤ who design travel schedules, control bedroom lighting and temperature, and even adjust competition start times when possible.

Every cell in the human body follows an internal timer known as the circadian rhythm, a roughly twenty-four-hour cycle ① that governs when we feel alert and when we feel drowsy. This clock is regulated primarily by a tiny cluster of neurons in the brain ② that responds to light entering through the eyes. When morning sunlight strikes the retina, the cluster signals the body ③ to 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 ④ 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 out of sync with the external environment. Such misalignment does not simply cause tiredness; it has also ⑤ been associated with digestive problems and reduced concentration, suggesting that timing matters as much as total sleep hours.

Time-management researchers frequently mention a principle ①known as Parkinson's Law, which states that work expands to fill the time available for its completion. According to this idea, a task that could be finished in one hour will often stretch to fill an entire afternoon if that much time ②is scheduled for it. Students who set vague deadlines frequently experience this effect, spending extra hours ③refined a report that was already complete. Employees given a full week for a simple project may also delay meaningful progress until the final days, even though the actual work ④requires far less effort. This pattern happens partly because people unconsciously adjust their pace to match perceived urgency. Setting shorter, more specific deadlines can counter this tendency, forcing tasks to fit within a tighter and more realistic window. By recognizing how flexible time encourages unnecessary delay, individuals can complete assignments more efficiently ⑤without sacrificing quality.

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.

Melatonin is a hormone produced by a small gland deep within the brain, and its release follows a remarkably predictable daily pattern. (A) This rhythm is controlled primarily by light: specialized cells in the eye detect brightness and send signals that either permit or suppress melatonin production, which is why exposure to bright screens late at night can delay its release and make falling asleep more difficult. (B) Levels stay low throughout the bright hours of the day, begin rising in the evening as darkness falls, peak in the middle of the night, and then decline again as morning approaches. (C) 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, preparing 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 intended.

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. (A) Elite endurance athletes typically post VO2 max values far higher than those of untrained individuals, reflecting hearts that pump larger volumes of blood and muscles that extract oxygen with remarkable efficiency. (B) While genetics accounts for a substantial portion of an individual's potential VO2 max, consistent aerobic training can still raise the measurement considerably over months of dedicated effort. (C) It is worth noting, however, that a high VO2 max does not guarantee success in competition, since other factors such as pacing strategy and mental resilience also play a decisive role.

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. (A) 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. (B) Sports nutritionists caution, however, that the timing and composition of meals matter as much as the total quantity of carbohydrate consumed. (C) The strategy is designed to maximize the amount of glycogen, the storage form of carbohydrate, packed into muscle tissue before competition begins.

This is precisely what makes the condition so difficult to catch before it becomes severe. Ambitious young athletes and the parents who support them sometimes assume that more training automatically produces better results, a belief that occasionally leads to a condition known as overtraining syndrome. ( ① ) Unlike ordinary fatigue that resolves after a few days of rest, overtraining syndrome develops gradually over weeks or months of insufficient recovery relative to training load, eventually producing persistent exhaustion, declining performance despite continued hard work, and increased susceptibility to illness and injury. ( ② ) Adolescents may be especially vulnerable, since their bodies are simultaneously coping with the physical demands of growth and the added stress of intensive training schedules. ( ③ ) Warning signs are often subtle at first, including disrupted sleep, irritability, and a loss of enthusiasm for a sport the athlete once genuinely enjoyed, which adults often mistake for ordinary moodiness. ( ④ ) Recovery from full-blown overtraining syndrome can take months rather than days. ( ⑤ )

Its influence, in fact, can persist quietly long after any feeling of alertness has faded. Caffeine is the most widely consumed stimulant in the world, prized for its ability to sharpen focus and fight off fatigue within minutes of consumption. ( ① ) It works by blocking adenosine, a chemical that gradually builds up in the brain throughout the day and makes us feel increasingly sleepy the longer we stay awake. ( ② ) By occupying the receptors that adenosine would normally bind to, caffeine tricks the brain into feeling alert even when the body has accumulated significant sleep pressure. ( ③ ) The effects, however, last far longer than most people realize. Because caffeine can remain active in the bloodstream for five to six hours, a cup of coffee consumed in the late afternoon may still be interfering with the ability to fall asleep at midnight. ( ④ ) Even when people do not consciously notice difficulty falling asleep, caffeine has been shown to reduce the amount of deep, restorative sleep obtained later in the night. ( ⑤ ) For this reason, many sleep specialists advise avoiding caffeine after early afternoon.