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Directions: Fill in each blank with a proper word chosen from the box. Each word can be used only once. Note that there is one more word than you need.

A. wraps       B. poorly       C. generating       D. incomplete       E. sufficient       F. further

G. Compressing       H. heats       I. uncertainty       J. pressurize       K. drowned

Neptune Rains Diamonds, and Now We Might Finally Know How

Deep within the hearts of Neptune and Uranus, it could be raining diamonds. Now, scientists have produced new experimental evidence showing how this could be possible.

The hypothesis goes that the intense heat and pressure thousands of kilometres below the surface of these ice giants should split apart hydrocarbon compounds, with the carbon【小题1】 into diamond and sinking even deeper towards the planetary cores.

The new experiment used the SLAC National Accelerator Laboratory’s Linac Coherent Light Source (LCLS)X-ray laser for the most precise measurements yet of how this “diamond rain” process should occur-and found that carbon transitions directly into crystalline diamond.

Neptune and Uranus are the most【小题2】 understood planets in the solar system. They are extremely far—only a single space probe, Voyager 2, has even been close to them, and only for a flyby, not a dedicated long-term mission.

The atmospheres of Neptune and Uranus are primarily made up of hydrogen and helium, with a small amount of methane. Below these atmospheric layers, a superhot, superdense fluid of “icy” materials such as water, methane, and ammonia【小题3】 the planet’s core.

And calculations and experiments dating back decades have shown that, with【小题4】 pressure and temperature, methane can be broken down into diamonds—suggesting that diamonds can form within this hot, dense material.

A previous experiment led by physicist Dominik Kraus used X-ray diffraction to demonstrate it. Now Kraus and his team have taken their research a step【小题5】 . “We now have a very promising new approach based on X-ray scattering,” Kraus said about their latest efforts. “Our experiments are delivering important model parameters where, before, we only had massive【小题6】. The more exoplanets we discover, the more relevant this will become.”

It’s challenging to replicate the interiors of giant planets here on Earth. The first step is to heat and【小题7】 the material to replicate the conditions inside Neptune at a depth of around 10, 000 kilometers: pulses of optical laser are 【小题8】 shockwaves in the polystyrene(聚苯乙烯), which【小题9】 the material up to around 5, 000 kelvin. It also creates intense pressure.

In the previous experiment, X-ray diffraction(衍射)was used to then probe the material. This works well for materials with crystalline structures, but less so with non-crystalline molecules, so the picture was【小题10】 In the new experiment, the team used a different method, measuring how X-rays scattered off electrons in the polystyrene.

This allowed them not just to observe the conversion of carbon into diamond, but also what happens to the rest of the sample-it splits off into hydrogen. And there’s pretty much no leftover carbon.

2023高二上·全国·专题练习
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Directions: After reading the passage below, fill in each blank with a proper word given in the box. Each word can only be used once. Note that there is one word more than you need.
A. advances               B. colonize               C. concerns               D. eventually            E. extremely
F. face                      G. spread                  H. stop                    I. surface               J. survive   K. visit

Living in Space

Stephen Hawking, one of the world’s most important scientists in history, believed that to survive, humans must move into space: “Once we 【小题1】out into space and establish independent colonies, our future should be safe,” he once said.

Today, the European Union, India, China, Russia, and Japan are all planning to send astronauts back to the earth’s closest neighbor: the moon. Some of these countries want to create space stations there between 2020 and 2030. These stations will prepare humans to 【小题2】and later live on Mars or other earthlike planets.

Robert Zubrin, a rocket scientist, thinks humans should 【小题3】space. He wants to start with Mars. Why? He thinks sending people to Mars will allow us to learn a lot — for example, about the ability of humans to live in a very different environment. Then we can 【小题4】create new human societies on other planets. In addition, any 【小题5】 we make in the fields of science, technology, medicine, and health will also benefit us here on the earth.

However, not everyone thinks sending humans into space is a smart idea. Many say it’s too expensive, even if it’s just a short journey. A one-way trip to Mars, for example, would take about six months. People travelling this kind of distance 【小题6】many health problems. Also, these first people would find life 【小题7】difficult out in space. On the moon’s 【小题8】, for example, the sun’s rays are very dangerous. People would have to stay indoors most of the time.


Despite these 【小题9】, sending people into space seems certain. In the future, we might see lunar cities or even new human cultures on other planets. First 【小题10】: the moon.
Directions: Fill in each blank with a proper word chosen from the box. Each word can be used only once. Note that there is one word more than you need.
A. qualities     B. continued     C. bodies     D. essential     E. transformations
F. described     G. geological     H. shaped     I. estimated     J. cultivated     K. evolved

For the first time, scientists have mapped the whole surface of Titan, the largest moon around Saturn. The map confirms existing data showing that Titan has many Earth-like 【小题1】 that might be able to support life.

The data was collected by Cassini, a spacecraft operated by the U.S. space agency NASA. The spacecraft studied Saturn and its moons from 2004 to 2017. Astronomers used images and radar measurements from Cassini to create the 【小题2】 map of Titan.

The map shows Titan as a mixture of flat plains, hills and mountains, windblown sand areas, valleys and lakes. The mapping operation is 【小题3】 in a report published in Nature Astronomy.

Rosaly Lopes led the project. She is a planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. Lopes told the publication that the many similarities between Earth and Titan make the Saturn moon a great choice for 【小题4】 exploration.

“Titan has an atmosphere like Earth's. It has wind; it has rain; it has mountains,” Lopes said.

Titan is the only planet in our solar system besides Earth to have known 【小题5】 of liquid on its surface. But Titan's seas and lakes are filled with liquid methane (甲烷) rather than water.

At cold temperatures, methane goes through similar 【小题6】 as rain does on Earth. It falls to the surface across the planet to form rivers and lakes and can then evaporate (挥发) to form clouds again.

The map found that nearly two-thirds of Titan's surface is made up of flat plains, Nature reported. About 17 percent is covered in sandy hills 【小题7】 by the wind, mostly around the equator.

Unlike Earth, Titan's sand is made up of carbon, hydrogen, nitrogen and oxygen. Around 14 percent of the surface is considered hilly or mountainous. Seas and lakes filled with liquid methane cover a(n) 【小题8】 1.5 percent of Titan. The liquid exists mainly closer to the planet's poles, while the equatorial areas remain drier.

Rosaly Lopes says organic materials --- those containing carbon --- in Titan's atmosphere are 【小题9】 for the growth of living organisms. “Organics are very important for the possibility of lifeon Titan, which many of us think likely would have 【小题10】 in the liquid water ocean under Titan's icy crust (硬的表面),”she said.

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