Level 4

Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.

In the morning when thou risest unwillingly, let this thought be present: I am rising to the work of a human being.

An AI tool can produce a short summary of a long text.

The face of the water, in time, became a wonderful book — a book that was a dead language to the uneducated passenger, but which told its mind to me without reserve, delivering its most cherished secrets as clearly as if it uttered them with a voice.

It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife.

Very soon after I went to live with Mr. and Mrs. Auld, she very kindly commenced to teach me the A, B, C.

Finishing a demanding chapter can be satisfying, especially when an idea that confused you at the beginning becomes clear by the end.

For nineteen years Halloran had kept the light burning on the rock at the harbor mouth, and in all that time not a single ship had wrecked on his watch.

When Reza arrived at the interview, the receptionist glanced at his coat and her face softened into recognition.

We tend to treat attention as if it were free, as if we could spend it everywhere at once and lose nothing.

Ada Lovelace was born in England in 1815, when women had limited access to advanced mathematical education.

Harriet Tubman was born into slavery in the United States in the early 1820s.

In the 1300s, the empire of Mali in West Africa was ruled by a king named Mansa Musa.

Picture a meadow open to every herder in a village.

Some apps and websites earn much of their income from advertising.

We tend to imagine memory as a recording, a faithful video stored away and replayed on demand.

Among Earth's resilient animals are tardigrades, often called water bears.

The human brain contains roughly eighty-six billion nerve cells called neurons.

Sunlight reaches only the upper layers of the ocean.

Spider silk combines strength with an ability to stretch.

Many people believe they must think first and write afterward, as if writing were merely the tidy report of a finished thought.

When something breaks, a common reflex is to replace it.

The Stoic philosopher Epictetus distinguished what depends on our own judgment and choice from what does not depend on us alone.

A community library receives six identical art kits.

When two explanations both fit the facts, which should you believe?

You have paid for a concert ticket that cannot be refunded or resold, and on the evening of the show you feel exhausted and unwell.

One way to increase production is the division of labor.

When protection shifts some consequences of a risky choice to someone else, it can change the incentive to take care.

Imagine a town whose first footpath bends around a wet field.

When you tap a button in an app and something happens, you are standing on top of a tower you cannot see.

The ministry sent Aurel to redraw the map of Valea because the old one had become a polite fiction.

Herr Bruns had two rules.

Imagine two people preparing meal boxes and making signs for an event.

A used-car seller may know years of service history, while a buyer has had only a short inspection.

An interest rate expresses a borrowing charge as a percentage, usually stated per year.

In the Republic, Plato asks his readers to imagine prisoners who have spent their whole lives chained in a cave, facing a blank wall.

In A Treatise of Human Nature, David Hume noticed a shift in moral arguments.

In 1971 the political philosopher John Rawls proposed a test for fair rules.

A short story near the end of the second chapter of the Zhuangzi describes a striking dream.

Potatoes reached Europe from the Andes in the sixteenth century.

In 1854, cholera killed hundreds of people around Broad Street in Soho, London.

Before standard time became widespread, towns often set clocks using local solar time.

Cognitive dissonance is discomfort associated with a conflict between beliefs, or between a belief and an action.

A child already enjoys drawing.

When a stranger cuts in front of you in traffic, you may think the driver is selfish before asking whether a lane is closing.

In the third edition of his county atlas, Aurel Brenner drew a hamlet named Kessel where no hamlet stood.

For two years Neve was the understudy in a play she never performed.

An antibiotic can change which bacteria survive.

On a clear day, the sky overhead looks blue.

Reactions caused by cosmic rays in the atmosphere produce carbon-14, an unstable form of carbon.

Fire can help some trees reproduce, though its effects depend on the forest and the severity of the burn.

A glacier forms where snow builds up over many years.

Zora Neale Hurston grew up in Eatonville, Florida, a self-governing Black town where stories, songs and conversation were part of daily life.

From 1799 to 1804, Alexander von Humboldt travelled through Spanish America with Aimé Bonpland, a French botanist and physician.

Fanny Mendelssohn, later Fanny Hensel, studied music alongside her younger brother Felix.

A measure is useful precisely because it is a simplification.

A translation can read so smoothly that the translator's work becomes almost invisible.

Tap water can cost very little per glass, yet supplying it requires an expensive network.

During the Second World War, repairs involving British and American equipment exposed a practical difficulty: fasteners made to different standards were not reliably interchangeable.

Internet traffic often arrives in bursts.

Insurance combines the risks of many policyholders.

Why might a small jeweler choose an expensive central shop while a furniture showroom seeks more space farther out?

Self-control is often pictured as a struggle: the student ignores a tempting game and keeps studying.

On a train, silence between strangers can seem like a treaty: an unwritten agreement that everyone prefers to be left alone.

On June 28, 1914, Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, made an official visit to Sarajevo with his wife, Sophie.

By autumn 1989, East Germany was leaking citizens through new routes to the West.

The piano had not been played in four years, Mrs. Aldous said, but she wanted it tuned.

Her father's workshop still smelled of pine shavings.

A national census aims to describe everyone living in a country at a particular time.

A small brass lantern hung outside a mountain inn.

For centuries, Timbuktu was connected to trade and scholarship across West and North Africa.

Imagine two job applicants who claim to be reliable.

A message crossing a noisy channel can change before it arrives.

An aurora can appear as a pale arc, a moving curtain, or rays across a dark sky.

Imagine Mara, a scientist who studies color vision in a room where everything is black, white, or gray.

The slime mold Physarum polycephalum, which can spread across damp wood, has no brain or central planner.

Imagine a community workshop that hung a banner saying EVERYONE WELCOME.

On Monday, an orange umbrella appeared in the lobby of Cedar House.

In a search for treatments against malaria, Chinese pharmaceutical researcher Tu Youyou and her team examined both modern screening results and historical medical writings.

Imagine that after a neighborhood meeting, Elena supports turning a parking space into a bench and assumes most residents agree.

If time zones followed geometry alone, the world could be divided into neat bands based on longitude.

A drum led a forest band that played each evening beside the river.

In the nineteenth century, a message between southern Australia and Britain traveled by ship and could take months.

Imagine two food shops facing the same square.

Suppose a library of digital documents contains millions of pages.

A wing moving through air produces lift through shape, angle, speed, and airflow.

Imagine a transporter that scans Leila, destroys the original, and builds a version on Mars.

Mantis shrimp have unusually complex eyes.

Some questions reward speed.

During evening power cuts, Tessa in apartment 14 and Arun in apartment 19 began signaling across the courtyard.

Lise Meitner built a career in physics when women faced formal and informal barriers in European universities.

A coach tells one team, “Eight of every ten players completed the course.”

On most days, a drill spends far more time on a shelf than in a hand.

Before the spring feast, Peacock decided that the village well looked too plain.

In some nineteenth-century Welsh industrial settlements, a row of homes shared a large bread oven.

In a simple sealed-bid auction, each bidder writes one offer without seeing the others.

An automated rain gauge can measure a shower without holding all the water that falls into it.

On a clear, calm night, a hollow at the foot of a slope may frost while trees higher up remain untouched.

A map can tell you where a marsh begins, a field guide can name its reeds, and a forecast can predict tomorrow's rain.

In a mature woodland, a nesting hole may serve more than one family.

At a repair counter, certainty can sound like competence.

Joon's maintenance cart announced him before he reached any door.

Leonardo da Vinci is often pictured as a solitary genius, but his education began in a busy Florentine workshop.

Read an unfamiliar claim once, and it may feel awkward.

Suppose a librarian wants to know how many books in a vast collection need repair.

A young moth claimed he could measure the Moon with one flight.

More than two thousand years ago, the Greek scholar Eratosthenes directed the Library of Alexandria in Egypt.

At a market with no posted prices, each sale begins as a fresh conversation.

A computer does not store a written character as ink or shape.

A bowl containing only ice and liquid water tends toward a balance near water's normal freezing point.

A meeting room contains one thermostat and twelve people.

A winter field looks sealed after deep snow, but the boundary between ground and snow can remain a habitat.

At my first community choir rehearsal, I followed the highest melody as if it were a bright ribbon.

The paper moon was already hanging above the puppet stage when Amara discovered that the rain box was empty.

When construction of the Brooklyn Bridge began in 1870, Emily Warren Roebling did not hold an engineering title.

Two volunteers are sorting unfamiliar hardware during a phone call.

Good wayfinding begins before a person reaches the place where paths divide.

A banyan spread its branches over half the village square.

In 1513, the Ottoman sailor and mapmaker Piri Reis completed a map of the Atlantic world.

A worker who moves to another city or country may regularly send part of each paycheck to relatives.

A software team releases a new version of an online service.

A lightning rod does not repel storms.

A person promises today to finish a difficult community project next year.

A tidal marsh occupies the shifting edge between land and water.

Beginning receives more ceremony than returning.

When Aunt Sela left Mara the narrow blue house, every room contained a clock.

Edmonia Lewis was the first widely recognized sculptor of African American and Native American heritage.

In an unfamiliar café, you suddenly feel this moment has happened before.

A cooper makes wooden vessels such as barrels, casks, buckets, and tubs.

A porcupine lived beside a bridge whose third plank had begun to split.

At a lighthouse, keeping a log was ordinary work.

A trader needs goods now but can pay after selling.

A group builds an air-quality sensor and publishes editable design files.

A growing tree uses atmospheric carbon to form new wood.

A thousand visitors each step off a marked trail once.

A narwhal's tusk is a tooth, usually a male’s left upper canine, that grows outward in a long spiral.

A bridge repair earns a photograph.

The book arrived with a note: “Found while clearing my mother's apartment.

The 1963 March on Washington for Jobs and Freedom brought over 200,000 people to Washington.

During a meeting, Priya thinks the new schedule is obviously helpful.

A building move begins before wheels turn.