영어 모의고사 (자동 편성)

Across many countries, high schools ① begins classes early 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 later, ② 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 ③ to wake before their bodies have completed a full sleep cycle, the mismatch accumulates into a chronic sleep debt ④ 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 ⑤ built around adult rhythms rather than adolescent ones.

After an especially demanding training session, the instinct to collapse onto a couch and remain motionless is understandable, yet exercise physiologists increasingly recommend the ① opposite approach. Active recovery involves performing low-intensity movement, such as a light jog, an easy swim, or a gentle bike ride, on days following intense exertion rather than resting completely. This gentle activity keeps blood circulating through tired muscles, which appears to help ② clear metabolic byproducts that accumulate during hard exercise more efficiently than complete stillness does. Some athletes worry that any movement at all will interfere with the repair process, but research suggests that truly light activity ③ accelerates healing considerably and may even reduce the perceived soreness that follows a hard session. The key distinction lies entirely in ④ intensity: active recovery is not a second workout in disguise but a deliberately gentle session designed to support, rather than compete with, the body's underlying repair ⑤ mechanisms.

Sleep debt refers to the ① cumulative gap between the amount of sleep a person needs and the amount they actually get. Unlike a financial debt, however, this deficit cannot simply be ② repaid with a single long weekend of rest. When someone loses two hours of sleep every night for a week, the body does not treat the shortage as fourteen separate small losses; instead, it ③ accumulates the deficit, and the resulting impairment in attention and mood can resemble that of a person who has been awake for an entire night. Researchers have found that even modest, chronic sleep restriction gradually impairs reaction time and decision-making, often without the affected person noticing the decline. This is because subjective feelings of tiredness tend to plateau after a few days, even as objective performance keeps deteriorating. Consequently, people frequently ④ underestimate how much sleep debt they are carrying until a demanding task suddenly exposes the ⑤ diminished cost.

Companies argue that this approach benefits consumers by showing advertisements that are more ①relevant to their actual interests rather than random, generic promotions. However, many critics contend that this level of tracking raises serious concerns about privacy, since users rarely understand how ②extensively their behavior is being monitored. Furthermore, personalized advertising can trap users in a narrow bubble, ③limiting their exposure to alternatives. Supporters counter that consumers who dislike targeted ads can simply adjust their privacy settings, though ④few people actually take the time to do so. Given these competing concerns, policymakers must strike a ⑤careless balance between allowing innovation and protecting individual privacy rights.

When a customer opens a company's website at midnight with a billing question, an actual employee is unlikely to be available, which is exactly the gap that customer service chatbots were built to fill. These programs can instantly answer common questions, track packages, and process simple refunds without making anyone wait on hold. Yet the technology has clear boundaries. When a customer's problem is unusual, emotionally charged, or simply does not fit the chatbot's script, _______________. Many companies have responded by designing chatbots to recognize their own limits, automatically transferring a frustrated customer to a human agent.

Smartphones, tablets, and computer screens all emit a significant amount of blue light, a short-wavelength light that our eyes are especially sensitive to. (A) At night, however, the same wavelength can interfere with the body's natural preparation for sleep by suppressing the release of melatonin. (B) During the day, exposure to blue light from the sun helps keep us alert and mentally sharp, which is generally beneficial. (C) For this reason, some devices now offer a night mode that shifts the display toward warmer tones, though sleep researchers still recommend limiting screen use before bedtime.

Sleep apnea is a disorder in which breathing repeatedly stops and restarts during sleep, often because the muscles at the back of the throat relax too much and block the airway. (A) Doctors therefore rely less on a patient's own account of the night and more on objective measurements, such as overnight oxygen levels and airflow patterns recorded in a sleep laboratory. (B) 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 waking up fully. (C) Because these interruptions rarely produce a clear memory the next morning, many people remain unaware that anything is wrong, even as chronic fatigue, headaches, and irritability build up over months.

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.

주어진 문장: Not everyone welcomes this shift, however, and some worry that it comes at a cost. As technology continues to reshape the job market, educators and employers increasingly agree on which skills will matter most in the coming decades. ( ① ) Technical literacy, including basic coding and data analysis, has become nearly as fundamental as reading and writing once were. ( ② ) Schools have begun redesigning curricula to emphasize problem-solving and adaptability, moving away from rote memorization toward project-based learning that mirrors real workplace challenges. ( ③ ) Most experts insist that a balanced combination of technical skill, adaptability, and communication will define successful careers ahead. ( ④ ) Communication skills matter as well, since many future jobs will require collaborating with both human colleagues and intelligent systems. ( ⑤ )

This process, though it may sound simple, triggers a remarkable series of adaptations throughout the cardiovascular system. Aerobic exercise, such as jogging, swimming, or cycling at a steady pace, strengthens the heart by forcing it to pump larger volumes of blood with each beat. ( ① ) Over weeks of consistent training, the heart gradually enlarges and becomes more efficient, meaning it can deliver the same amount of oxygen to working muscles while beating fewer times per minute. ( ② ) This adaptation explains why trained athletes often have a much lower resting heart rate than sedentary individuals of the same age. ( ③ ) Beyond the heart itself, aerobic activity encourages the body to build new capillaries within muscle tissue, improving the delivery of oxygen and nutrients at a cellular level. ( ④ ) Researchers have also found that regular aerobic exercise reduces inflammation throughout the body and improves the way cells respond to insulin. ( ⑤ )