영어 모의고사 (자동 편성)

Time travel to the past has long fascinated physicists and philosophers alike, but it also generates a famously troubling ①contradiction. Suppose a traveler journeyed backward in time and, through some combination of accident and intention, prevented their own grandfather from ever meeting their grandmother. If the grandfather never had children, the traveler themselves would never have been born, which means the traveler could never have existed to make the trip in the first place. Yet if the traveler never made the trip, the grandfather would have ②survived to meet the grandmother after all, allowing the traveler to be born and eventually travel back in time. The story therefore ③loops endlessly, undermining itself at every turn rather than settling into any stable outcome. Some physicists resolve the paradox by arguing that any consistent timeline must ④permit such self-defeating actions to succeed freely, while others propose that a traveler who alters the past simply branches off into a separate, parallel timeline instead, an idea many find ⑤appealing precisely because it avoids the contradiction altogether.

Consider a village green shared freely by every herder in the community, where each individual may graze as many animals as they wish without paying any fee. From the perspective of any single herder, adding one more animal to the shared pasture brings a clear personal ①loss, since the extra income belongs entirely to that herder alone. The cost of the additional grazing, however, is spread thinly across every herder who uses the green, so no single individual bears more than a tiny fraction of the ②damage. Because this calculation favors adding more animals for every rational herder, the shared pasture is gradually ③overgrazed until it can no longer support any animals at all, harming the very community whose rational members caused the collapse. Philosophers use this scenario to illustrate a troubling gap between what benefits an individual in the short term and what preserves a shared resource in the ④long term, a gap that voluntary self-restraint alone rarely ⑤closes.

A single fertilized egg eventually gives rise to every cell type in the human body, from neurons to bone, a feat that has ①fascinated biologists for more than a century. Embryonic stem cells retain much of that original ②versatility, capable in principle of developing into almost any tissue, which is why researchers have long viewed them as a promising raw material for repairing damaged organs. Because harvesting these cells traditionally required destroying a human embryo, the research ③eliminated ethical objections fierce enough to slow funding and legislation in several countries for years. A breakthrough arrived when scientists discovered that ordinary adult skin cells could be reprogrammed into a state resembling embryonic versatility without ever touching an embryo. These induced pluripotent cells have not entirely erased the ethical debate, but they have opened a path for stem cell research that far more scientists and funding agencies are ④willing to ⑤support.

Imagine a teleportation device that scans every atom in your body, transmits that information to a distant station, and reconstructs an exact physical duplicate there, while destroying the original body in the process. From the traveler's point of view, stepping into the machine and stepping out on the other side would feel utterly seamless, complete with continuous memories. Philosophers, however, are troubled by a version of the same device that malfunctions: instead of destroying the original, it leaves the original body intact while still creating a perfect duplicate elsewhere. Now two people exist, each with identical memories and an equally strong claim to being the original traveler, and there is no principled way to say that one of them is the real continuation of the person who entered the machine. This malfunction reveals that _______________.

Medieval philosophers told the story of a hungry donkey placed exactly midway between two identical, equally fragrant piles of hay, with no factor whatsoever tipping the balance toward either option. Because the donkey is assumed to be a perfectly rational creature that always chooses the option supported by the strongest reason, and because neither pile offers any advantage over the other, the donkey supposedly finds itself with no rational basis for choosing one pile rather than the other. Paralyzed by this perfect symmetry, the donkey starves to death precisely because it can find no reason to move in either direction. Critics of the story point out that _______________.

Political philosophers have long debated how much authority, if any, a government may legitimately claim over free individuals. Robert Nozick imagined a hypothetical starting point in which people live without any state at all, each relying on private arrangements to protect their own person and property. He argued that a minimal state, limited strictly to enforcing contracts and protecting citizens from violence, theft, and fraud, could arise gradually through a series of voluntary exchanges, without anyone's rights ever being violated along the way. Critics on one side, the anarchists, insist that even this minimal government inevitably violates the rights of those who never consented to join it. Critics on the other side argue that a state limited to bare protection cannot address deeper inequalities that arise naturally in any free market. Nozick's thought experiment therefore _______________.

Consider a large heap containing ten thousand grains of sand. (A) Something has clearly gone wrong along the way, since no reasonable person would call one grain of sand a heap, but pinpointing exactly which single removal transformed a heap into a non-heap seems impossible. (B) Nearly everyone agrees that removing a single grain from such a heap leaves another heap behind, since surely one grain could never make the difference between a heap and a non-heap. (C) Yet if this principle is applied repeatedly, grain by grain, the heap eventually shrinks to a single lonely grain, or even to no grains at all, and logic alone seems to force us to accept that this final result still counts as a heap.

Imagine a brilliant scientist named Mary who has spent her entire life inside a black-and-white room, learning everything physical science could ever teach about color. (A) Despite this complete physical knowledge, Mary herself has never actually seen a color, since every book, screen, and object in her world has been carefully restricted to shades of gray. (B) Suppose that one day Mary is finally released from the room and shown a ripe red tomato for the first time. (C) Philosopher Frank Jackson argued that Mary would learn something entirely new at that moment, namely what it actually feels like to see red, even though she already possessed every physical fact about color.

Bacteria have been cutting up invading viral DNA for billions of years, long before any scientist thought to borrow the trick for use in a laboratory. (A) Once Cas9 arrives at the target site, it slices both strands of the DNA helix, and the cell's own repair machinery rushes in to mend the cut, often introducing a small change in the process. (B) By supplying the cell with a template during this repair step, scientists can direct that machinery to insert a specific new sequence, and what once required years of painstaking work to alter a single gene can now be accomplished within days. (C) The CRISPR-Cas9 system, as it is now known, relies on a short guide RNA that matches a specific DNA sequence, leading a scissor-like enzyme called Cas9 directly to that exact location in the genome.

The cell then acts as a temporary factory, translating that instruction into an actual protein without ever altering the cell's permanent genetic code. For decades, most vaccines worked by injecting a weakened or inactivated version of a pathogen, coaxing the immune system into recognizing an enemy it had never truly fought. ( ① ) mRNA vaccines take a fundamentally different route, delivering only a short genetic instruction wrapped in a protective lipid capsule, one that tells the body's own cells how to manufacture a single harmless piece of a virus's outer surface protein. ( ② ) Once those cells display the fragment, the immune system learns to recognize it as foreign and builds a defense, without ever having encountered the actual pathogen. ( ③ ) Because the vaccine contains no live virus and cannot alter a cell's own DNA, developers can redesign the genetic instructions within weeks whenever a pathogen mutates. ( ④ ) This is far shorter than the years-long process required for traditional vaccines. ( ⑤ ) This speed, first proven on a global scale during a recent pandemic, has convinced many researchers that the same platform could eventually be adapted to fight diseases far beyond infectious illness, including certain cancers.