Placed among the busy streets of Washington, D. C. is a large public garden that many Americans have never heard of. The U. S. National Arboretum (植物园) includes
Government scientists are in charge of the 180-hectare area. Their main goal is
The arboretum is home to one of the
While the scientists do their work, the public
2 . Animals, including humans, feel sound as well as hear it, and some of the most meaningful communication happens at frequencies (频率) that people can’t hear. Elephants, for example, use these low-frequency sounds to, among other things, find family or a mate across long distances. Whales do it, too.
But you don’t have to weigh a ton to make a sound. In fact, you don’t have to be bigger than a pea. Consider, for example, the tree-hopper, a curious little animal that lives on the stems (茎) of the leaves. University of Missouri biologist Rex Cocroft has spent much of his time listening closely to tree-hoppers with his team.
The team discovers that all the sounds being heard from tree-hoppers are produced by males. They do it by vibrating (振动) their abdomens (腹部) to make a wide variety of strange sounds. There is almost no airborne sound produced with these vibrational sounds. Cocroft explained, “If a tree-hopper were to stand on your finger and produce a sound, you would feel the vibration but hear no sound.”
They showed that some sounds, not surprisingly, seem to be aimed at attracting females. And some are aimed at other males.
Cocroft explained, “When two males meet each other, or when they are mate-searching on a branch, we’re hearing ‘purring, bdddddrrrr…’ sounds that males give.” Normally, a person couldn’t hear any of this, because the sound travels along the stem, inside it. And that’s how other tree-hoppers detect it.
Cocroft said tree-hoppers have very sensitive legs. And they stand around on stems, which are good at spreading vibrations. So they just use what nature gives them to communicate with each other.
“They have so many different forms of social behavior and grouping,” Cocroft explained. “And once there are animals living in groups, then there will be all sorts of interesting possibilities for communication.”
1. What does Cocroft’s research focus on about tree-hoppers?| A．Their variety. | B．Their communication. |
| C．Their living areas. | D．Their numbers. |
| A．They sense sounds by legs. |
| B．They knock the stems to make sounds. |
| C．Their sounds can be easily heard by humans. |
| D．Females make sounds to meet each other |
| A．It is key to their survival. |
| B．It drives an increase in their numbers. |
| C．It often leads to communication. |
| D．It contributes much to the division of animal types. |
| A．A Magic Moment in Nature | B．A Journey to the Wildlife |
| C．Learning From Nature | D．Communication Sounds Among Animals |
3 . Every year the start of the Atlantic hurricane season is another reminder for Margarite August that she still doesn’t have a roof.
The 70-year-old retired teacher’s home on the small Caribbean island nation of Dominica was mostly wiped out by hurricane Maria six years ago.
Six years after hurricane Maria, Dominicans like Margarite August still haven’t been able to rehabilitate their homes.
August is not alone. Since Maria, the government of Dominica has built 7,000 new homes—about a quarter of its housing stock-with materials to fight another Category 5 hurricane. They’ve also relocated two communities. But an untold number of the island’s 70,000 or so residents are like August, rebuilding their homes in any way they can afford.
Hurricane Maria is often referred to as a once-in-a-lifetime disaster. Scientists put much of the blame on warming ocean temperatures that could make frequent (频繁的) storms like it.
Maria damaged a terrible 95% of Dominica’s housing stock and 226% of the nation’s GDP. Before the storm, the country’s economy had long struggled since its independence from Great Britain in 1978. Unlike its more famous touristy neighbors along the chain of eastern Caribbean islands it lies on, Dominica is more known for its rugged mountains and jungles (丛林) than white sandy beaches.
The jungle mountains that crash down to the coast are beautiful but disasters visit easily. “I don’t think anybody ever got over Maria,” says Christine John of the Dominica Red Cross. “There are a lot of persons today—if it just starts to rain outside, they get anxious.”
1. What does the underlined word “rehabilitate” in paragraph 3 mean?| A．Rebuild. | B．Leave. | C．Decorate. | D．Buy. |
| A．Over-farming. | B．Loss of the land. |
| C．The disappearance of the forests. | D．Climate change. |
| A．Its good economy. | B．Its architecture. |
| C．Its mountains and jungles. | D．Its sandy beaches. |
| A．They have to stay bored at home. | B．Their houses are easy to take in water. |
| C．They don’t know how to make umbrellas. | D．They are afraid of another disaster like Maria. |
Waters may be flowing on the surface of an enormous planet that lies about 120 light-years from Earth, according to new evidence
The investigation with the space-based observatory, one of the most advanced astronomy instruments in operation,
The Webb telescope, which can detect infrared (红外) light invisible to the human eye, searched for exactly
And even if scientists confirm the chemical compound’s presence, that doesn’t guarantee life-forms exist there. But this new evidence does expand scientists’ understanding of exoplanets similar
5 . Amur tigers, also known as Siberian tigers, are interesting animals. They are the biggest cats in the world. A full-grown Amur tiger can weigh over 600 pounds. Unlike lions that live in groups, tigers are solitary animals. Tigers also have very good eyesight and hearing. Its eyesight is six times better than a human’s.
Amur tigers live in the forests located in the Russian Far East and northeastern China. They have a thick yellow fur coat with black stripes(条纹). Their stripes are like human fingerprints. Every tiger has a different and unique stripe pattern. Tigers use their striped coat to hide themselves from the animals they hunt. Their thick fur and a thick layer of fat keep them warm during the long, cold winters in the forest.
As powerful and quiet hunters, Amur tigers usually hunt at night. Sometimes these tigers travel hundreds of miles looking for food. They hunt deer and wild boar(野猪) that live in the forest. They also hunt smaller types of bears. A hungry Amur tiger can eat more than 50 pounds in one night.
Today, Amur tigers are an endangered species. People illegally hunt Amur tigers. Amur tigers are also still in danger because the forests they live in are being destroyed. Illegal logging(砍伐) and new roads destroy their forest homes. It makes it hard for the tigers to find food. It also makes it difficult for the tigers to travel for long distances. They almost disappeared forever at the beginning of the 20th century—They were hunted until only 40 tigers remained in the wild.
Countries like Russia then began to protect these big cats. They made it illegal to hunt them and tried to protect their forest habitat. After these changes, the number of Amur tigers living in the wild increased. Scientists believe there are about 540 Amur tigers living in the wild today.
1. What does the underlined word “solitary” in the first paragraph mean?| A．Scary. | B．Smart. | C．Nonsocial. | D．Big. |
| A．They feature the same stripe pattern. | B．They have bad eyesight and hearing. |
| C．They have no need to hide themselves. | D．They often go hunting when night falls. |
| A．Methods and effects of tiger protection. |
| B．The number of tigers in various countries. |
| C．The differences in the living habits of tigers. |
| D．Reasons for tigers becoming endangered animals. |
| A．Where Do Amur Tigers Live? | B．The Interesting but Endangered Amur Tigers |
| C．The World’s Largest Lions | D．How Many Tigers Are Left in the World? |
6 . Cancer-fighting genes in elephants could help tackle one of the biggest killers of people, according to research. Despite their large bodies and long lifespans, elephants are much less likely to die from cancer than humans, with death rates of less than 5 percent.
The paradox has puzzled scientists because more cells lead to greater replications (复制), which increases the possibility of the body failing to detect damaged DNA or a faulty cell that can result in tumors(肿瘤). Elephants live for almost as long as humans and weigh up to five tons.
However, a group of British and European scientists say they have taken a big step towards solving Peto’s paradox, named after the British epidemiologist Sir Richard Peto. Elephants, they say, carry a much larger more diverse group of tumor-fighting proteins.
The findings, published last week in the journal Molecular Biology and Evolution, raise hopes that the cancer fighting genes in elephants could be the key to tackling cancer, which kills about 167, 000 Britons yearly. Cells keep dividing throughout an organism’s life, each carrying the risk of producing a tumor. One of the body’s weapons is a gene called p53 known as the “guardian of the genome”, which hunts cells with faulty DNA. It encourages the cell to repair itself or self-destruct, keeping the cell from combining with others and producing tumors.
Humans have two versions of p53 but elephants have 40, said the researchers. Biochemical analysis and computer simulations also showed that an elephant’s p53 genes are structurally slightly different, providing a much larger anti-cancer toolkit. The researchers suspect that while faulty cells might be able to skirt two p53 versions, they cannot combine with other cells as easily in the face of dozens.
The findings will open the way for research on how p53 genes of elephants are activated and on medical treatment for humans.
1. What has puzzled scientists?| A．Few elephants end up dying from cancer. | B．Elephants live long and weigh enormously. |
| C．More cells lead to higher chances of tumors. | D．A larger body is less likely to discover faulty cells. |
| A．How many Britons die each year. | B．How the anti-cancer gene works. |
| C．How the research was carried out. | D．What the findings have been applied to. |
| A．Strengthen. | B．Detect. | C．Escaped. | D．Cure. |
| A．Scientists find elephants live longer than humans. | B．P53 genes play essential role in preventing cancer. |
| C．Elephant genes could be key to fighting cancer. | D．Groundbreaking treatment for cancer is on the way. |
One sunny Saturday morning, I got ready for a hike with my classmates. I was so excited about it since it was my first time to go hiking. I ate a light breakfast just a few slices of bread and an egg. After that I grabbed my backpack and hurriedly ran out of my house and then met my classmates at the school gate. At that time I didn’t think that there would be a terrible disaster ahead.
The jungle (丛林) that we are going to was far from our area. Its name was Salymbia Jungle. The drive was 3 hours long but it was not a dull ride as we were all eager about the hike and we bad each other’s company. We appointed a guide and his name was Thomas. He said that he had hiked in the Salymbia Jungle lots of times, and he was familiar with the pathways. When we arrived, Thomas allowed us to begin. There were a wide variety of plants which I had never seen before. The smell of the jungle was so earthy. All of us were amazed by the beauty of the scenery and the sound of the creatures.
After a while we were walking and then I looked at my wrist (手腕) to check the time but then I realized my watch had fallen off. Then I walked back without telling anyone. I did not worry about getting lost since there were other persons behind and I thought I would have been able to catch up with my classmates. I went back searching the pathway and I lost track of time and lost sight of my classmates. I immediately realized that I was alone.
After I realized I was lost, the first thing I did was to check my phone to see how far away I was from my companions. However, I was having no luck because there was no network in my phone, which made my phone practically useless.
Paragraph 1: The sky started to become darker.___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Paragraph 2: As I was falling asleep, I heard a human voice.
___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
8 . Wetlands, making up about 6% of Earth’s land surface, are found on every continent except for Antarctica.
Protecting against floods. Wetlands play a crucial role in protecting against floods. The plants and soil in wetlands act as natural sponges (海绵), storing excess water during heavy rainfall or storms.
Purifying (净化) water. Wetlands have exceptional abilities to purify water. Acting as natural filters, the plants, soil and micro creatures in wetlands remove sediments, excess nutrients and pollutants from water sources.
Fighting climate change. Aside from these vital functions, wetlands also play a significant role in fighting climate change.
However, the world’s wetlands are being lost at an alarming rate. Restoration and conservation projects offer hope that these ecosystems can be saved.
| A．Supporting life |
| B．Protecting birds |
| C．This process helps to improve water quality |
| D．The water stored in wetlands can be drunk |
| E．Wetlands play an important role despite their small coverage |
| F．Wetland plants have remarkable carbon storage capabilities |
| G．Thus, wetlands can reduce the risk of flooding in surrounding areas |
9 . Forecasters say Floridians should monitor a system likely to become a tropical depression(热带低压)as it moves into the Gulf of Mexico by early next week.
The area of low pressure over the northwestern Caribbean Sea was producing showers and thunderstorms, according to a Friday evening update from the National Hurricane Center. Condition s favor slow development over the next several days, and forecasters expect the system will become a tropical depression early next week while moving north over the eastern Gulf of Mexico.
Michael Brennan, the National Hurricane Center director, said in a live video Friday, “There is a lot of uncertainty with this system since it’s yet to take shape. What we’re most confident in is that there will likely be some rainfall impacts across much of the Florida Peninsula and possibly up along the southeast coast of the United States.”
The potential threat for Florida would come around on Tuesday, said Brian McNoldy, a researcher at the University of Miami. McNoldy added that global models were in agreement that the system would develop slowly. The hurricane center on Friday gave the system the temporary name of Invest 93L, meaning forecasters would collect specialized data and run more models.
According to Mark Luther, a professor at the University of South Florida, tropical systems like to feed off that hot water, especially when it’s hot below the surface like it is now. “Keep a sharp eye on it and have your hurricane plan in place,” Luther said. “Even if it’s a small storm, if it hits at the right angle, it can cause flooding around here.”
Storms that cross through this steamy section of the eastern Gulf of Mexico have historically intensified(增强)quickly. Hurricane Michael in 2018 emerged off the Yucatán Peninsula before ultimately making landfall as a Category 5 storm in Florida’s Panhandle.
1. What did Brennan think would most likely happen next week?| A．Water shortage. | B．Severe damage. |
| C．Fine weather. | D．Heavy rainfall. |
| A．Ask for clear guidance. | B．Be watchful about possible disasters. |
| C．Make a quick decision. | D．Send relief to flood victims at once. |
| A．To express his heartfelt thanks for the rescue effort. |
| B．To erase scientists’ doubts about these global models. |
| C．To prove the weather forecast is timely and accurate. |
| D．To explain the tropical system may bring heavy storm. |
| A．A news report. | B．A diary entry. |
| C．A children’s story. | D．A research paper. |
10 . In the office of remote sensing scientist Liu Shaochuang, there is a huge photograph of a camel he snapped a decade ago in Xinjiang. He crouched for hours by a pool of water in the Gobi Desert to capture the image.
Since 2012, he has led a team in tracking and studying wild camels using satellite remote sensing technology.
Unlike zoologists who focus on species, Liu has studied the interrelationship between endangered animals and their environment, which he believes will help develop better protection strategies in the face of climate change.
His interest in wild camels began when his team tested a prototype(雏形)design of the lunar rover Yutu in the desert. Living in the harsh deserts in northwestern China and southwestern Mongolia, camels are listed as critically endangered animals. Experts estimate that the population of this species is currently less than 1, 000, of which around 650 are in China.
“Ten years ago, the research relied solely on human observation, which was very primitive, ”Liu says. Because camels are fully migratory and can travel over long distances, scientists used to learn their habits by studying hoof prints and droppings. It was hard to find one camel in the desert, let alone track it. But Liu thought his expertise in satellite navigation(导航)and remote sensing might come in useful in the study of wild camels.
It was not easy at first. Liu learned zoology from scratch. His team had to spend several weeks each year braving dust and sandstorms in the vastness of the Gobi Desert seeking out camels. A scar on his right eyebrow is the result of a rollover accident on a rugged mountain road in Xinjiang.
“The most exciting moment was attaching a satellite positioning collar to a wild camel. ”The tracking collar, equipped with special receivers, weighs only a few hundred grams. It can detach automatically and will not have a negative impact on the daily lives of the animals. The locations of the tracked animals are transmitted via satellite every day. Based on the data, scientists can get to know their migratory paths, living environments and possible threats they may meet with.
For Liu, it is worth the significant sci-tech effort to study such a rare species. He adds wildlife protection and research will become more precise and efficient with the help of technology.
1. What was it that made tracking wild camels difficult?| A．The number of camels experienced a sharp decline. |
| B．Massive migration made camels cover huge distances. |
| C．Primitive tools were used in human observation. |
| D．Hoof prints and droppings were never to be seen. |
| A．His carelessness in carrying out his research. |
| B．His inexperience at the very beginning of his work. |
| C．The rough conditions under which he worked. |
| D．The stress he met with in his work. |
| A．The formation of the tracking collar. |
| B．The definition of the tracking collar. |
| C．The importance of the tracking collar. |
| D．The function of the tracking collar. |
| A．Generous and ambitious. | B．Confident and grateful. |
| C．Creative and determined. | D．Optimistic and modest. |
