1 . The Best Caves in The World
Hang Son Doong, Vietnam
Natural caves don’t come much larger than Hang Son Doong, close to the border between Laos and Vietnam. This cave possesses the largest cross-section of any known cave on the planet, a vast area that is difficult to describe. Supposedly, a Boeing 747 could fly through without damaging its wings, but that doesn’t really do justice to the vastness of Hang Son Doong. The stalactites (钟乳石) here are pretty massive too, with some reaching up to 80 metres.
Waitomo Caves, New Zealand
Glowworms (萤火虫) are there, as far as the eye can see. Okay, not literally, but the Waitomo Cave system on New Zealand’s North Island is best-known for the fluorescent fauna that light up the walls, giving it the not-particularly-creative but completely acceptable “Glowworm Caves” nickname. They are more accessible than other caves on this list, with rafting and adventure tours available to those looking for something a little more thrilling.
Mammoth Cave, the USA
If you have certain expectations from somewhere called “Mammoth Cave”, that is entirely understandable. Mammoth Cave in Kentucky is the world’s longest known cave system, an incredible 420 miles of underground wonder. That’s twice as long as the next longest, by the way, although it isn’t unusual for the USA to go all out on such things.
Reed Flute (芦笛) Cave, China
Named after the reeds that grow outside, which are used to make flutes, obviously, the Reed Flute Cave’s walls are covered with inscriptions from centuries gone by—if evidence was needed that people have been paying attention to this place for a long old time. The inside part of the cave is also lit up by multicoloured lights, giving it a real otherworldly theme that adds weight to the nickname.
1. What is special about Hang Son Doong?| A．It was once a base of a factory. |
| B．It is the deepest cave in the world. |
| C．It has the highest stalactites in the world. |
| D．It owns the largest cross-section in the world. |
| A．Hang Son Doong. | B．Waitomo Caves. |
| C．Mammoth Cave. | D．Reed Flute Cave. |
| A．Vietnam. | B．New Zealand. | C．The USA. | D．China. |
2 . The popular documentary series Aerial China (航拍中国) recently returned to the small screen. The latest and fourth season of it gives a perspective that is both excellent and informative. As the final of the series, the new season was shot across 11 provincial-level regions and started in the spring of 2020.
“The experience from the previous three seasons makes us more capable to follow wild animals while avoiding disturbing them,” says Yu, chief director of the series. China has made great efforts to protect endangered wildlife species and their habitats in recent years, and it has become much easier to spot rare species in the wild. Taking Tibetan antelopes as an example, the plateau-based creatures were difficult to encounter in the past, but the expansion of their population and enhanced research on their living patterns have allowed the camera crew to tailor plans to follow the animals.
Most close-ups for the season were shot by photographers from helicopters or cameras installed on drones (无人机). The vital moment for a successful shot depends on the mood of the animals or how good the weather is,” Yu says. In an attempt to fully show China’s huge changes over the past decade, the documentary series consulted experts from different fields to help select the most attractive shooting sites. In the final season, Aerial China has used 73 helicopters and 320 drones to shoot footage over an area of 900,000 kilometers, and selected around 1,000 staffers. More than 30 teams were assigned to shoot in different cities for the fourth season.
The previous three seasons have been watched by 850 million TV viewers and seen online over140 million times. For fans of the series, the director says he hopes that the new season will draw a bigger audience with its unusual perspective to show them China like never seen before.
1. Which can best replace the underlined word “perspective” in the first paragraph?| A．Reference. | B．Viewpoint. | C．Mention. | D．Standard. |
| A．To indicate a successful encounter. | B．To introduce new living patterns. |
| C．To show a biological improvement, | D．To save endangered wildlife species. |
| A．The team members’ roles. | B．The splendid shooting sites. |
| C．The hi-tech devices for shooting. | D．The efforts spent in the season. |
| A．This is the last but one season. | B．This season is well worth viewing. |
| C．The series is popular with TV reviewers. | D．The series is intended for Chinese fans. |
3 . This summer we witnessed interview teams at the North Pole wearing short sleeve shirts due to the warm weather. A study published on Aug 29 revealed more concerning issues in the supposedly coldest area of the world. Zombie ice from a massive Greenland ice sheet was confirmed to be melting, which would eventually raise global sea levels by at least 10 inches (27 centimeters) on its own, reported Associated Press (AP).
Zombie ice is the kind of ice that is still attached to thicker areas of ice, but is no longer getting fed by larger glaciers. Since glaciers are getting less snow to complement the amount of ice melted, once the zombie ice is melted, it cannot be re-formed.
Scientists decided to look at the balance of the ice. In perfect equilibrium (平衡), snow in the mountains of Greenland flows down and thickens the sides of glaciers, balancing out what’s melting on the edges, according to AP. But in the last few decades, there is less refill and more melting, creating an imbalance.
Study co-author William Colgan told AP that 3.3 percent of Greenland’s total ice volume will melt eventually. “Starving would be a good phrase for what’s happening to the ice”, Colgan added.
With a great number of natural resources buried under the earth, areas of melted ice revealed treasures that attracted the world’s richest men. According to CNN, in early August, there was a “treasure hunt” in Greenland. Billionaires, including Bill Gates and others, financially backed KoBold Metals, a US-based mineral exploration company, to explore the rare metals under the glaciers in Greenland. The company told CNN that since there were enough minerals to power hundreds of millions of electric vehicles, the critical resource is capable of powering the green energy transition. While investors are taking advantage of global warming, experts feared that the mineral exploration is likely to worsen the local environment, draining up the world’s resources at a faster rate.
1. According to the text, what can we infer about zombie ice?| A．It’s complemented by nearby glaciers. |
| B．It will melt away from the ice cap. |
| C．It’s independent from large glaciers. |
| D．It has increased by up to 10 inches. |
| A．Why more zombie ice can’t be created. |
| B．How zombie ice is usually formed. |
| C．What the melting of zombie ice can lead to. |
| D．How zombie ice functions in the ecosystem. |
| A．The ice has brought about starvation. |
| B．The ice is refilled more than before. |
| C．The ice is becoming gradually thinner. |
| D．The ice has been good to skate on. |
| A．Supportive. | B．Tolerant. | C．Indifferent. | D．Worried. |
4 . In the 1960s, while studying the volcanic history of Yellowstone National Park, Bob Christian-sen became puzzled about something that, strangely, had not troubled anyone before he couldn’t find the park’s volcano. It had been known for a long time that Yellowstone was volcanic in nature—that is what accounted for all its hot springs and other steamy features. But Christian-sen couldn’t find the Yellowstone volcano anywhere.
Most of us, when we talk about volcanoes, think of the classic cone(圆锥体)shapes of a Fuji or Kilimanjaro, which were created when erupting magma(岩浆)piled up. These can form remarkably quickly. One day in 1943, a Mexican farmer was surprised to see smoke rising from a small part of his land. In one week he was the confused owner of a cone five hundred feet high. Within two years it had topped out at almost fourteen hundred feet and was more than half a mile-across. Altogether there are some ten thousand of these volcanoes on Earth, all but a few hundred of them extinct. There is, however, a second less known type of volcano that doesn’t involve mountain building. These are volcanoes so explosive that they burst open in a single big crack, leaving behind a vast hole, the caldera(火山口).Yellowstone obviously was of this second type, but Christian-sen couldn’t find the caldera anywhere.
Just at this time NASA decided to test some new high-altitude cameras by taking photographs of Yellowstone. A thoughtful official passed on some of the copies to the park authorities on the assumption that they might make a nice blow-up(放大的照片)for one of the visitors’ centers. As soon as Christian-sen saw the photos, he realized why he had failed to spot the caldera: almost the whole park—2.2 million acres -was a caldera. The explosion had left a hole more than forty miles across-much too huge to be seen from anywhere at ground level. At some time in the past Yellowstone must have blown up with violence far beyond the scale of anything known to humans.
1. What does the underlined word “its” in paragraph 1 refer to?| A．The ground. | B．The nature. |
| C．The volcano. | D．The park. |
| A．A single big crack was forming there. | B．Someone was burning stalks there. |
| C．A volcano was erupting underneath. | D．There were some hot springs there. |
| A．By looking at the photographs. | B．By analyzing its steamy features. |
| C．By researching historical documents. | D．By using some advanced equipment. |
| A．Its level is much higher than the surrounding areas. |
| B．The volcano in it involved mountain building. |
| C．It is a large hole left by the explosion. |
| D．Its shape is much like a cone. |
5 . For those who have been wishing for real-life chocolate mountains, your dream is about to come true! Just kidding. The chocolate look-alike mounds (土丘) in Bohol, Philippines have absolutely nothing to do with chocolate aside from the fact that during one particular time of the year, they appear to look similar to chocolate.
During the wet season and anytime outside of the dry season, the Chocolate Hills maintain a green color. What attracts people’s attention is the shape of these mounds, as they look as though they were placed there by design, but none of these fields are man-made.
With regard to the origin of the Chocolate Hills, while experts have their own opinions, it’s the Filipinos who have drawn their own conclusion about the Chocolate Hills. According to a popular legend, these hills were a result of two giants (巨人) who ended up throwing mounds of earth at one another during a heated argument. As the fight heated up, they began throwing things such as rocks and sand, which is said to be what created the surrounding area. While some locals believe the legend and some don’t, it is an interesting story nevertheless and fun to think about.
However, the real story lies in the composition (成分) of the hills and this is where experts have a bit more of a scientific reason for the hills being there than just giants. With the help of heavy rainfall and erosion (侵蚀), it’s believed that limestone (石岩) was broken down over time and it’s this dissolution (分解) that created the Chocolate Hills.
The dry season in the Philippines is the only time to see these hills in all their chocolatey glory, and that falls between late November and May. However, since it is just the predicted dry season, it’s recommended that visitors check the weather before planning anything.
1. What is the color of the Chocolate Hills in the wet season?| A．Yellow. | B．Green. | C．Brown. | D．Grey. |
| A．A legend about the Chocolate Hills. |
| B．Locals’ opinions about the Chocolate Hills. |
| C．Who created the Chocolate Hills. |
| D．What the Chocolate Hills are made up. |
| A．the dissolution of limestone | B．the lack of rainfall |
| C．human activities | D．the extreme dry climate |
| A．Early November. | B．Mid-July. |
| C．Late September. | D．Early January. |
6 . If you’ve ever worried that we’ve solved all the mysteries of nature, fear not. Minnesota’s Devil’s Kettle Falls has been attracting hikers and geologists for generations. At the falls, along Lake Superior’s North shore, a river forks at a rock outcrop. While one side runs down a two-step stone bank and continues on like a normal waterfall, the other side falls into a deep hole and disappears apparently forever.
And this baffling situation only gets strange when geologists start explaining Devil’s Kettle (水壶). Consider, for instance, the sheer quantity of water pouring into the kettle every minute of every day. While the idea of some kind of broad, underground river is an exciting device in movies, the reality is that those sorts of deep caves are rare.
Another idea is that millions of years ago, a hollow lava tube may have formed beneath the falls, in the subsurface layer of rock. Over time, the theory suggests, the falling water eroded (侵蚀) the surface and fell straight down into the ancient lava tube, providing wide-open access to the floor of Lake Superior. Again, there are problems with this theory, because no lava tubes have ever been found in any of the hundreds of exposed rock beds in the area.
In February 2017, scientists said that water that disappears into the rock at Devil’s Kettle rises again in the stream below the falls. To confirm the theory, scientists plan on conducting a dye trace during a low-water flow period. They’ll pour a vegetable-based dye into the pothole and watch where the dye comes to the surface again.
“What we think is happening is that the water is going in the kettle, and coming up pretty close to immediately downstream of the falls,” Green said.
Green admits that if the dye is found below the falls like the scientists suspect, then much of the Devil’s Kettle Falls mystery will be gone. “Were there a little bit of that,” he said, “the folks would not be going to stand there and wonder. But it will still be a fascinating spot, and a beautiful spot.”
1. What is the purpose of writing the first paragraph?| A．To explain the formation of waterfalls. |
| B．To describe a beautiful landscape scene. |
| C．To introduce a mysterious natural phenomenon. |
| D．To recommend an unusual waterfall to readers. |
| A．Supportive. | B．Curious. | C．Doubtful. | D．Indifferent. |
| A．By tracing the path of the water. |
| B．By controlling the direction of the stream. |
| C．By asking the folks to watch the surface. |
| D．By filling the pothole with a dye. |
| A．The mystery of Devil’s Kettle Falls |
| B．The discovery of Devil’s Kettle Falls |
| C．The disappearance of Devil’s Kettle Falls |
| D．The fascinating features of Devil’s Kettle Falls |
7 . Many people assume Egypt is, and always has been, a desert. But considering that climates and landscapes can change over time and that humans have been known to change natural environments, was ancient Egypt a desert?
The simple answer is no. Not all of Egypt, ancient or modern, qualifies as a desert. Areas near the Nile River tend to be lusher (草木繁茂的), and Egyptians — in both ancient and modern times — have had a successful system of agriculture. However, the environment has changed over Egypt’s history, and the construction of the Aswan High Dam (坝) across the Nile between 1960 and 1970 changed the landscape greatly.
Some areas of Egypt that are now desert were wetter in the past. One famous example is the “Cave of Swimmers” in southwestern Egypt. Today, the area is very dry, but thousands of years ago, it was wetter, and some of the rock art found in caves in the area appears to show people swimming, according to the British Museum.
The Aswan High Dam caused some areas in southern Egypt to flood, leading to the creation of Lake Nasser. Many people had to move, and some archaeological (考古的) sites ended up underwater. The construction of the dam also ended the natural flooding of the Nile. The creation of Lake Nasser also led to more moisture (水分) in the air in some areas of southern Egypt.
One effect of the generally higher Nile River levels during the Bronze Age is that around 2500 B. C., when the pyramids at Giza were constructed, the “Khufu branch”, a vanished (消失的) branch of the Nile River, came right next to the pyramids (金字塔). This branch allowed for materials to be transported to the site by boat, aiding in pyramid construction.
The ancient Egyptians who lived by the Nile in some ways viewed themselves as living on an island in the Nile Valley, with the deserts as a sort of great sea.
1. What can we know about “Cave of Swimmers”?| A．It used to be very dry. | B．The rock art shows it used to be wet. |
| C．It’s near the British Museum. | D．It shows ancient Egyptians loved art. |
| A．It saves some Egypt archaeological sites. |
| B．It brings in too much trouble for Egyptians. |
| C．It affects Egypt both positively and negatively. |
| D．It leads to more moisture in the air in the whole Egypt. |
| A．By making Nile River water level higher. |
| B．By helping people build pyramids more easily. |
| C．By making ancient Egyptians live on an island. |
| D．By leading some branches of the Nile River disappear. |
| A．Was Ancient Egypt a Desert? | B．Do You Know Deserts in Egypt? |
| C．Was Egypt a Great Country? | D．Do You Know Ancient Egypt? |
8 . WHAT ARE RIP CURRENTS?
Rip currents are like the rivers of the sea, transporting water near the shore back out into the ocean depths. The presence of these currents can be hidden by the wild movements of the surrounding waves. This means that as well as carrying seaweed and pieces of materials quickly out to sea, they can rapidly sweep away even the strongest swimmers. Around 80 percent of all lifeguard rescues are caused by powerful rip currents pulling a swimmer into danger.
If you find yourself being pulled out to sea by an unsuspected rip current, you should remain calm, focus on staying afloat and, if you can, swim parallel to the shore. Your instincts might tell you to swim towards land, as this is where you’re aiming to get to, but the current will be too strong to swim against. Instead, aim to move across the current and into slower flowing water next to it. A rip current may only pull you just past the breaking waves, but in some cases they can take you hundreds of metres offshore. The strength of currents can be hard to predict, so it’s safest to stay on lifeguarded beaches and not to swim if you see any indication of a rip current.
| A．prevent you from swimming into danger | B．transport water out into the ocean depths |
| C．clear away seaweed and pieces of materials | D．warn lifeguards against rescue in rip currents |
| A．difference between various currents | B．two types of zones off shore |
| C．an ideal route to surf in safety | D．how rip currents form |
| A．1000 metres off the shore beyond “HEAD”. | B．The channel through the gap in a sandbar. |
| C．The location where a red flag is erected. | D．Over the narrow stretch of a sandbar. |
9 . Wildfire, or wildland fire, is the uncontrolled fire occurring in a forest, grassland or bushlands.
Fire danger in a wildland setting varies with weather conditions: drought, heat, and wind. Once a fire is burning, drought, heat, and wind all increase its intensity. Topography(地形) also affects wildfire, which spreads quickly uphill and slowly downhill. Dried grass, leaves, and light branches are considered flash fuels, and fire spreads quickly in them, often generating enough heat to burn heavier fuels such as tree stumps(树桩), heavy branches, and the organic matter of the forest floor. Such fuels, ordinarily slow to burn, are difficult to extinguish. Green fuels—growing vegetation-are not considered to catch fire easily, but an intense fire can dry out leaves and needles quickly enough to allow ready burning. Green fuels sometimes carry a special danger. Evergreens, such as pine and spruce(云杉), contain oils that easily burst into flames when heated sufficiently by the searing drafts(灼热的气流) of a forest fire.
Firefighting forces are specially trained to deal with wildfires. Aircraft were first used in fighting wildland fires in 1919. Now airplanes and helicopters are primarily used for dumping water, for observation, and occasionally for assisting in communication and transporting personnel, supplies, and equipment
Tools for fighting wildfires range from the standard equipment of urban fire departments to portable pumps, tank trucks, and earth-moving equipment. It can also change the fire’s direction as well as slowing its progress. They are maintained by public and private owners of forestlands. Such a force may attack a fire directly by spraying water, beating out flames, and removing vegetation at the edge of the fire to contain it behind a fire line. When the very edge is too hot to approach, a fire line is built at a safe distance, sometimes using strip (长条地带) burning to get rid of the fuel in the path of the uncontrolled fire.
1. What is Paragraph 2 mainly about?| A．What causes wildfire to happen. |
| B．How topography affects wildfire intensity. |
| C．Why wildfire danger hides in green fuels. |
| D．Where wildfire often breaks out. |
| A．Carrying thin leaves. A. When the fire dies down. |
| B．Having heavy branches. |
| C．Lacking enough water. |
| D．Containing some oil. |
| A．When the fire dies down. |
| B．When the wind blows hard. |
| C．When the fuel burns uncontrollably. |
| D．When the pump works effectively. |
| A．An advertisement brochure. |
| B．A news report. |
| C．A sci-fi lecture, |
| D．A geography magazine. |
10 . Ho Khanh is a middle-aged farmer, living in a village on the edge of Phong Nha-Ke Bang National Park in Vietnam. What is special about him is that he has discovered Son Doong, the largest cave in the world.
“I first found the cave about thirty years ago, in 1991,” he says. “I was out collecting firewood near the national park. My family were very poor, so I decided to go deeper into the forest to find some aloe, which is very valuable. Not many people went that far into the forest because they were afraid of the wild animals.”
Soon Khanh lost his way. “I sat down with my back to a huge round rock,” he says. “Then I heard the sound of a strong wind and running water coming from behind me.” He found the entrance to a huge cave, with a wide river coming out of it. Khanh thought he was walking into a great cave. With no ropes or lights, he did not go further into it.
Khanh’s story spread like wildfire, but not everyone believed him. “I wanted to prove that I was telling the truth, but I couldn’t remember the way to the cave.” Then one morning early in the winter of 2006, a group of cavers from Britain came to ask Khanh for help, as they had heard about his discovery fifteen years before.
Khanh agreed to help the team to find the cave, but after three days in the jungle, they lost their way. “I just couldn’t remember where it was,” he says. The team came back twice, but each time they were beaten by the thick jungle. Finally the cavers left.
In 2009, Khanh headed to the jungle one cold winter’s morning. “I stopped by a big round rock,” he says. “There was the same strong wind, the sound of water running — I knew I’d found the cave at long last.” Soon the British cavers returned and followed Khanh on a six-hour trip deep into the jungle. On April 14 they found Son Doong.
1. What is the text mainly about?| A．How Son Doong was discovered. | B．How Son Doong got its name. |
| C．A young farmer in Vietnam. | D．A national park in Vietnam. |
| A．looking for aloe | B．collecting firewood |
| C．catching some animals | D．cutting down trees in the forest |
| A．They doubted it. | B．They believed it. |
| C．They were uncertain of it. | D．They had little interest in it. |
