영어 모의고사 (자동 편성)

Sleep is not a single, uniform state but a cycle that alternates between two very different modes: REM (rapid eye movement) sleep and non-REM sleep. During non-REM sleep, especially its deepest stage, the brain waves slow down dramatically, the body temperature drops, and tissue repair and growth hormone release reach their peak. This is the period ①most closely associated with physical restoration. REM sleep, by contrast, brings rapid eye movements, near-total muscle paralysis, and brain activity that closely ②resemble wakefulness. Most vivid dreaming occurs during this stage, and researchers believe it ③plays a central role in consolidating memories and processing emotional experiences. A healthy night typically cycles through both stages four or five times, with non-REM ④dominating the early hours and REM periods lengthening toward morning. Disrupting either stage, through frequent awakenings or alcohol use, can leave a person ⑤feeling unrested even after a full night in bed.

After a viewer finishes an episode, a streaming service rarely ①leave the choice of what to watch next entirely up to chance. Instead, a recommendation algorithm compares that viewer's habits with patterns ②drawn from millions of other users who watched similar content, then ranks thousands of titles in order of predicted interest. This approach keeps viewers engaged far longer than a simple list of new releases ever could, which is precisely why streaming companies invest so heavily in ③refining it. The system is not without drawbacks, however. Because the algorithm favors titles similar to what a viewer already enjoys, it can quietly narrow someone's exposure to unfamiliar genres, directors, or cultures, ④creating a comfortable but repetitive bubble. Some platforms have begun inserting occasional wildcard suggestions, deliberately unrelated to past viewing habits, in an attempt ⑤to counteract this narrowing effect.

Browsing an online store today often means ①chatting with an AI assistant that asks a few quick questions, such as budget or intended use, before suggesting a short list of products tailored to the answers. Unlike a static list of best-sellers, this assistant can adjust its suggestions on the spot, ②responding to follow-up questions the way a knowledgeable salesperson might in a physical store. Retailers report that shoppers ③who use these chatbots tend to complete purchases more often and return fewer items, since the guided conversation helps buyers choose products that actually fit their needs. Some shoppers, however, remain wary of how personal the questions can feel, ④wonder how much of that conversation is quietly stored and reused to influence future purchases. Consumer advocates argue that stores should clearly explain what happens to this data, rather than ⑤burying the explanation in a lengthy privacy policy.

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

In recent years, mental health experts have identified a distinct emotional response to environmental crisis, commonly called eco-anxiety. Eco-anxiety describes persistent worry, grief, or fear triggered by awareness of climate change and its consequences for the future. Although people of all ages can experience it, teenagers and young adults seem especially ①immune, since they anticipate living through decades of worsening conditions. Common symptoms include difficulty sleeping, a sense of ②hopelessness, and guilt over ordinary choices such as travel or diet. For example, some students report feeling ③paralyzed whenever they read alarming climate news, unable to focus on schoolwork or hobbies. However, experts emphasize that eco-anxiety is not a disorder to be eliminated but a ④natural reaction that can be channeled productively. Rather than avoiding the topic, young people are encouraged to join community projects, since taking constructive action tends to ⑤restore a sense of control and ease overwhelming distress.

Caffeine is the most widely consumed stimulant in the world, prized for its ability to ①sharpen focus and fight off fatigue within minutes of consumption. It works by blocking adenosine, a chemical that gradually builds up in the brain throughout the day and makes us feel ②decreasingly sleepy the longer we stay awake. 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. 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 ③interfering with the ability to fall asleep at midnight. Even when people do not consciously notice difficulty falling asleep, caffeine has been shown to ④reduce the amount of deep, restorative sleep obtained later in the night. For this reason, many sleep specialists advise ⑤avoiding caffeine after early afternoon.

Open a music streaming app on any given morning, and a personalized playlist is usually already waiting, assembled overnight from songs the algorithm predicts will match a listener's current mood. Listeners often praise the feature for introducing them to artists they never would have searched for on their own. Musicians, meanwhile, have mixed feelings about this shift in how audiences discover new music. A song that the algorithm decides not to promote may struggle to reach listeners no matter how well it was written, meaning that _______________.

A navigation app calculating a route rarely relies on distance alone; instead, it constantly weighs real-time traffic reports, past congestion patterns, and even data from other drivers' phones currently on the road. This flood of information allows the app to reroute a driver away from a sudden accident within seconds. The convenience comes at a cost that few passengers consider, however. When thousands of drivers are simultaneously redirected onto the same shortcut, _______________, arguing that an algorithm optimizing for individual convenience can end up creating a new, entirely different problem for the wider community.

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.

After an especially demanding training session, the instinct to collapse onto a couch and remain motionless is understandable, yet exercise physiologists increasingly recommend the opposite approach. (A) This gentle activity keeps blood circulating through tired muscles, which appears to help clear metabolic byproducts more efficiently than complete stillness does. (B) Some athletes worry that any movement at all will interfere with the repair process, but research suggests that truly light activity does not meaningfully slow healing. (C) 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.