Scientists say they have found detailed evidence of ancient rivers on Mars. The discovery supported existing evidence that Mars once had water. The researchers said their findings suggested rivers may have flowed on the surface of Mars for hundreds of thousands of years.
These images were captured by a camera on NASA’s Mars Reconnaissance Orbiter. The camera is able to take detailed pictures of the surface while orbiting the planet from about 400 kilometers away. A team of scientists studied the images, which showed a valley network on Mars.
The team was led by Francesco Salese, a geologist at Utrecht University in the Netherlands. Salese said the scientists studied sedimentary (沉淀物) rocks from a 200 meters high rocky cliff. Sedimentary rocks form when sedimented (使沉积) and transported by water or wind.
“These are sedimentary rocks and were formed by rivers that were likely active for over 100,000 years,” Salese said, adding even without the ability to examine the cliff area on Mars, the pictures show strong similarities to sedimentary rocks found on the earth.
William McMahon is another geologist who was part of the investigation team. He said sedimentary rocks have long been studied on the earth to learn what conditions were like on our planet millions or even billions of years ago. Another leader of the team was Joel Davis, a researcher with Britain’s Natural History Museum. He said scientists had never before been able to examine such a rock formation with such great detail. They created 3D images of the area to get a more detailed understanding of it, which suggested some ancient Martian rivers were several meters deep.
1. What is the text mainly about?| A．Scientists are able to study rock formation on Mars. |
| B．Scientists found evidence that there was water on Mars. |
| C．Mars sedimentary has many similarities to that on the earth. |
| D．A camera on NASA’s Mars Reconnaissance Orbiter took pictures of the planet. |
| A．By comparing data. |
| B．By analyzing images. |
| C．By studying rivers on the earth. |
| D．By observing Mars through a telescope. |
| A．Excited. | B．Unsatisfied. | C．Unexpected. | D．Disappointed. |
| A．A novel. | B．A notebook. | C．A travel guide. | D．A newspaper. |
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【推荐1】Hoping to live on the moon one day? Your chances just got a tiny bit better. Researchers found that lunar pits and caves reach stable temperatures, making them potentially suitable for human life.
Planetary scientists at the University of California, Los Angeles have been doing the research. Although much of the moon’s surface temperatures ranges from as high as 260 degrees during the day to as low as 280 degrees below zero at night, the moon has pits and caves where temperatures stay at roughly 63 degrees Fahrenheit, making human habitation a possibility, according to their new research.
For perspective, a day or night on the moon equals a little over two weeks on the earth—making long-term research and habitation difficult with such extremely hot and cold temperatures. Researchers say these stable spots could transform the future of lunar exploration and long-term habitation. The shadowed areas of these pits could also offer protection from harmful elements, such as solar radiation, universal rays and micrometeorites (微小陨石).
About 16 of the over 200 discovered pits most likely come from collapsed lava tubes—tunnels that form from cooled lava or crust, according to Tyler Horvath, a UCLA doctoral student and head of the research. The researchers think overhangs inside of these lunar pits, which were initially discovered in 2009, could be the reason for the stable temperature.
The research team also includes UCLA professor of planetary science David Paige and Paul Hayne at the University of Colorado Boulder. “Humans evolved living in caves, and to caves we might return when we live on the moon,” said Paige in a UCLA press release.
There are still plenty of other challenges to establishing any sort of long-term human residence on the moon—including growing food and providing enough oxygen. The researchers made clear that NASA has no immediate plans to establish a base camp or habitations there.
1. What did the researchers find?| A．Humans like the life on the moon. |
| B．People lived in lunar pits and caves. |
| C．Steady temperature exists somewhere on the moon. |
| D．Temperatures in caves and pits vary a lot on the moon. |
| A．Solar heat. | B．Harmful liquids. | C．Universal gases. | D．Micrometeorites. |
| A．Appeared. | B．Developed. | C．Hunted. | D．Escaped. |
| A．It has no such plans. | B．Food there tastes bad. |
| C．Many challenges exist. | D．There is no oxygen. |
【推荐2】Since I was born and brought up in a rural town，I have a great interest in nature.Using the chance of studying abroad in my second year at college，I decided to go to Canada just because I wanted to see the beautiful phenomena there.So after I finished the study program，I went to Yellowknife in the Northwest Territories.
I clearly remember the sixth night in Yellowknife.Suddenly my host mother came to my room around 8∶00 p. m.and told me to change clothes and go outside quickly carrying her camera.
The northern lights were flickering (闪烁) in the sky！I was shocked and just stood there with my mouth open.I forgot to take pictures of the mysterious lights.
Since that night，whenever it was sunny，I went outside at night and looked at the sky.It was so cold that I lost all feeling in my hands and feet.
As I took pictures of the northern lights，I came to find a characteristic movement of the lights.They first appear in the north part of the sky and then they gradually come down to the south part of the sky.After that，suddenly，they come in the middle of the north and south only for a while，which is the time when the best northern lights can be seen.Since it is only a few seconds for the northern lights to come down to the middle of the sky，it is very hard to get good pictures.
The stronger the sun acts，the better and stronger the northern lights flicker in the sky.That's because they come about from the collisions (碰撞)between atmospheric gases and the solar wind.Much more solar wind comes to the earth when the sun is active，which leads to the best northern lights.And the colors of the northern lights depend on the height of the collisions and the kinds of gases.
1. What does the last paragraph mainly tell us?| A．Ways to take good pictures. |
| B．The relationship between the sun and the northern lights. |
| C．The colors of the northern lights. |
| D．The time of the best northern lights. |
| A．She wanted to take a picture of him. |
| B．She wanted to take a walk with him. |
| C．She wanted to tell him something important. |
| D．She wanted him to see the northern lights. |
| A．the host mother didn't remind him to take the camera |
| B．he was shocked by the wonderful sight |
| C．the lights flickering in the sky disappeared too soon |
| D．he lost all feeling in his hands and feet |
| A．When they appear in the north part of the sky. |
| B．When they come down to the south part of the sky. |
| C．When they are between the north and south. |
| D．When they rise in the east part of the sky. |
【推荐3】Why should mankind explore space? Perhaps the best answer lies in our genetic makeup as human beings. What prompted our distant ancestors to move from the trees into the plains, and on into all possible areas and environments?
Exploration also allows minerals and other potential resources to be located. Additional resources are always beneficial when used wisely, and can increase our chances of survival. Knowledge or techniques acquired through exploration, or preparing to explore, filter from the developers into society at large.
In certain circumstances, life on Earth may become impossible: over-population or wide spread diseases, for instance, might eventually force us to find other places to live. While the earth is the only planet known to sustain life, surely the adaptive ability of humans would allow us to inhabit other planets and moons. It is true that the lifestyle would be different, but human life and cultures have adapted in the past and surely could in the future.
| A．The techniques may have medical applications which can improve the length or quality of our lives. |
| B．Space allows us to expand and succeed: for the sake of everyone on the earth, now and in the future, space exploration is essential. |
| C．The mysterious space objects varying in size have been fascinated scientists and scholars for years. |
| D．It appears that we are driven to ensure the success and continuation of not just our own genes, but of the species as a whole. |
| E．Therefore it still poses a problem for us human beings whether to explore the space at the cost of our own homelands. |
| F．While space may hold many wonders and explanations of how the universe was formed or how it works, it also holds dangers. |
【推荐1】Houston may be the last place you would expect to see a tiger wandering, but private ownership and breeding (哺育) of big cats is a Texas-sized problem in the United States. While tiger ownership is banned in Houston, it is legal in most parts of Texas. In some other states, it is even easier to buy a tiger than to adopt a dog from a local animal shelter.
In America, young tigers can be purchased from the pet market, online and elsewhere. These tigers in private hands grow quickly into large and dangerous animals that few people are equipped to handle. As a result, some may end up as body parts sold on the black market, fueling the illegal wildlife trade. Tigers in the wild have a territory of at least 18—and up to 1,500—square kilometers. To confine (关押) them to a cage, home or backyard is unquestionably cruel.
Another thing, wild animals make for dangerous pets. A tame animal is not the same thing as a domesticated (驯养的) animal. A tiger in the house is still a tiger. It keeps all the same traits as a tiger in the wild. Tigers can pose dangers, whether they are born in a forest or in a cage. Undoubtedly, a thinly-regulated private ownership of tigers in the U.S. has created a public safety nightmare.
South Africa has approved a ban on captive-bred lion industry. Authorities worldwide are also waking up to the cruelty of breeding big cats for commercial purposes. The incident in Houston should serve as a wake-up call to ban private ownership and the breeding of big cats.
Americans should urge their government to ban the backyard breeding industry. At the same time, the most effective thing we can do is to support organizations that are working to protect tigers in their native, wild habitats.
The unfortunate truth is that the population of tigers in the wild has declined over the last century from 100, 000 to about 3,900. By some estimates, there are twice that many in captivity in America. Tigers belong to forests, grassland and valleys. They’re not supposed to be in backyards, in selfies, and certainly not in a Houston neighborhood.
1. What does the underlined word “Texas -sized” in paragraph 1 mean?| A．Enormous. | B．Practical. | C．Technical. | D．Uncomplicated. |
| A．It is a cruel act for wildlife. |
| B．It will stimulate illegal wildlife trade. |
| C．It poses a danger to the common public. |
| D．It introduces trouble to the management of the pet market. |
| A．By introducing a concept. | B．By making comparisons. |
| C．By explaining statistical data. | D．By referring to a previous study. |
| A．To introduce the habits of wild tigers. |
| B．To call for awareness of the dangers of backyard breeding. |
| C．To urge the American government to stop private ownership of tigers. |
| D．To inform people of the seriousness of private tiger ownership in the U.S. |
【推荐2】From the moment we are born, we interact with the world through movement. We move our lips to smile or to talk. We extend our hand to touch. How does our brain remember this wide range of motions? How does it learn new ones? How does it make the calculations necessary for us to grab a glass of water, without dropping it, squashing it, or missing it?
Technion Professor Jackie Schiller from the Ruth and Bruce Rappaport Faculty of Medicine and her team examined the brain at a single-neuron (单神经元) level to shed light on this mystery. They found that calculation happens not just in the interaction between neurons, but within each individual neuron. It turns out that each of these cells is not a simple switch, but a complicated calculating machine.
This discovery, published recently in the Science, promises changes not only to our understanding of how the brain works, but better understanding of conditions ranging from Parkinson’s disease to autism. And if that isn’t enough, these same findings are expected to advance machine learning, providing inspiration for new architectures.
“We used to think of each neuron as a sort of whistle, which either rings, or doesn’t,” Prof. Schiller explains. “Instead, we are looking at a piano. Its keys can be struck at the same time, or in order, producing an infinity (无限) of different tunes.” This complex music playing in our brains is what enables us to learn and perform an infinity of different, complex and precise movements.
These same findings can also serve as an inspiration for the machine learning community. Deep neural networks, as their name suggests, attempt to create software that learns and functions somewhat similarly to a human brain. Although their advances constantly make the news, these networks are primitive compared to a living brain. A better understanding of how our brain actually works can help in designing more complex neural networks, enabling them to perform more complex tasks.
1. Why does the author raise the questions in paragraph 1?| A．To pursue answers. | B．To raise his puzzles. |
| C．To introduce the topic. | D．To share his interest |
| A．The result of the research. |
| B．The function of a single neuron. |
| C．The way the research was conducted. |
| D．The aspects the discovery can be applied to. |
| A．The way that neurons work. |
| B．The music that neurons play. |
| C．The difficulties that researchers encounter. |
| D．The process where neurons produce memory. |
| A．Individual Neuron Works like a Piano |
| B．Calculation Happens Between Neurons like a Machine |
| C．Complex Neural Networks in the Brain Enable People to Learn |
| D．The Mystery of Learning and Remembering Movement Has Been Uncovered |
【推荐3】New smart wheelchairs are designed to allow users more freedom of movement. Some even allow them to raise or lower the seats or to go up and down stairs. Now, Scewo, a Swiss company, has designed their futuristic motorized wheelchair Scewo Bro that is a complete solution with multitasking innovation. This smart wheelchair is so advanced and multifunctional that it won the Design Prize in 2018 and has been recognized as a pioneer in the medical technology industry.
With clearly defined lines and a reduction to the essentials, the design team developed a clear design language. That way, Scewo Bro is seen as a new generation of wheelchairs at first glance. Scewo Bro users can control the wheelchair either by a touch interface (界面) or a smartphone. They can switch from one to the other and can also choose from three different modes: park mode, drive mode, and track mode. This allows for any terrain (地形) and for people with mobility disabilities to be independent.
Built with safety in mind, the seat always balances itself so the user stays in a sitting position. This feature allows users to deal with different terrains without the risk of tipping over. Besides, the foot rests, seat, and arm rests are designed to be comfortable and adjustable.
The smart wheelchair can go up to 35 kilometers on one charge and can go 10 kilometers per hour. If a break is needed, just put the chair into the relaxation position. The smart wheelchair comes with two secure storage areas for people on the go to store valuables. It can fit in the trunk of a car and can be charged in just five hours.
Scewo Bro is available in Switzerland, Austria, and Germany. While the first batch(首批) has sold out, people can pre-order for delivery at the end of 2021. This futuristic wheelchair will allow for increased movement and a better quality of life for people with mobility issues.
1. What do we know about the wheelchair?| A．It targets medical workers. |
| B．It features more functions. |
| C．It is designed for household use. |
| D．It is the first motorized wheelchair. |
| A．Its design philosophy. |
| B．Its working principle. |
| C．Its customer experience. |
| D．Its fashionable elements. |
| A．By giving exact figures. |
| B．By making comparisons. |
| C．By offering examples. |
| D．By listing reasons. |
| A．The wheelchair needs further improvement. |
| B．The company Scewo is a non-profit organization. |
| C．The wheelchair users can move around independently. |
| D．The design team has been awarded many design prizes. |
