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Recently, Google researchers published a paper describing results from an artificial intelligence (AI) tool, called MusicLM, built to create music. It is not the first AI music tool to launch. But the examples Google provides demonstrate musical creative ability based on a limited set of descriptive words. AI shows how complex computer systems have been trained to behave in human-like ways.

Google engineers explain the MusicLM system this way: First, a user comes up with a word or words that describe the kind of music they want the tool to create. For example, a user could enter this short phrase into the system: "a continuous calming violin backed by a soft guitar sound." The descriptions entered can include different music styles, instruments or other existing sounds. Several different music examples produced by MusicLM were published online. Some of the generated music came from just one-or-two-word descriptions, such as "jazz", or "techno". The system created other examples from more detailed descriptions containing whole sentences. In the resulting recording, the music seems to keep very close to the description. The team said that the more detailed the description is, the better the system can attempt to produce it.

In addition to generating new music from written descriptions, the team said the system can also create examples based on a person's own singing, whistling or playing an instrument. The researchers said the tool "produces high-quality music… over several minutes, while being faithful to the text conditioning signal".

Although it hasn't been released for public use, Google announced it was releasing a "high-quality dataset (数据集)" of more than 5,500 music-writing pairs prepared by professional musicians called MusicCaps. The researchers took that step to assist in the development of other AI music generators.

The MusicLM researchers said they believe they have designed a new tool to help anyone quickly and easily create high-quality music selections. However, the team said it also recognizes some risks linked to the machine learning process.

Scientists have come up with a new way of identifying animals in an area by testing DNA taken in from the air. The researchers believe their new method could help scientists keep track of animals that are hard to spot, including endangered animals.

Two teams of scientists—one in Denmark and one in the United Kingdom (UK)—came up with the same question at about the same time: Could they identify the animals in an area from DNA that was simply floating in the air?

Testing for eDNA isn't a new idea, but most of the time, scientists look for eDNA in water. DNA in the air is usually so small that it would take a microscope to see it. The scientists didn't have high hopes for their experiment. Neither team knew that the other group was working on a similar experiment. One collected samples from different locations at Denmark's Copenhagen Zoo, and the other at Hamerton Zoo Park in the UK. The scientists used slightly different methods to collect their samples. But basically, both teams collected extremely tiny bits of DNA onto very high quality filters.

In the laboratory, they got the DNA from the filters and made copies of it to study. By comparing their samples with examples of DNA from different animals, the scientists were able to identify many different animals at the zoos.

Each team only discovered about the other experiment after they had written a paper about their own results. Instead of competing, the two decided to combine their results and publish a paper together.

Both teams are excited about the ways this new method could be used in the wild. Scientists have been looking for better ways to track endangered animals without interfering with them. If researchers know where animals live, they can do a better job of protecting them. "The next step is to figure out how to take this method into nature," says Dr. Bohmann, one of the scientists on the Copenhagen team.

Most people have heard of Shakespeare and probably know something of the plays that he wrote. However, not everybody knows much about the life of this remarkable man, except perhaps that he was born in the market town of Stratford upon Avon and that he married a woman called Anne Hathaway. We know nothing of his school life. We do not know, for example, how long it lasted, but we presume that he attended the local grammar school, where the principal subject taught was Latin.

Nothing certain is known for what he did between the time he left school and his departure for London. According to a local legend, he was beaten and even put in prison for stealing rabbits and deer from the estate of a neighboring landowner, Sir Thomas Lucy. It is said that because of this he was forced to run away from his native place. A different legend says that he was apprenticed to a Stratford butcher, but did not like the life and for this reason decided to leave Stratford.

Whatever caused him to leave the town of his birth, the world can be grateful that he did so. What is certain is that he set his foot on the road to fame when he arrived in London. It is said that at first he had no money or friends there, but that he earned a little by taking care of the horses of the gentlemen who attended the plays at the theatre. In    time, as he became a familiar figure to the actors in the theatre, they stopped and spoke to him. They found his conversation so brilliant that finally he was invited to join their company.

The following are newly released devices all designed to help make your life more convenient, beautiful and vivid.

Tonal

$2,995 AT TONAL.COM

Tonal makes lifting and resistance training truly easy and accessible from your own home. It is great because I hate any sort of public weight training. Tonal has a remarkably easy user interface and gives data and feedback in a helpful manner. It also makes you feel great by keeping track of clear improvements.

Hisense 75'' U 800GR 8K ULED Roku TV

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8k sounded like a luxury, but now that brands like Hisense, which focus on a more affordable end of the spectrum, have gotten some time with the tech, you can finally bring the deep color output and stunning detail into your living room. Calling it "affordable" may be a stretch, but compared to most 8k TV's which all run over $5,000, it's the most cost-efficient version of the tech we've got.

VIVE Goggle

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Vive goggles will bring an extremely accessible and refreshing approach to the VR world. They are a pair of goggles not unlike something you'd wear to snowboard. They're extremely lightweight with a lightning fast set—that's connected with things like watching Netflix. It's the calmest headset I've ever worn and uses cameras to let you control everything with just your hands. This one's for the not-gamers.

Dyson Purifier Humidify+Cool Formaldehyde

$920 AT WALMART

For people who easily sneeze because of dog hair or something like that outside, Dyson has created a machine that saves them for time at home. This new purifier doubles as a humidifier, plus it has a cooling function, making it the end all be all for stuffy, hot, dry apartments.

 请用英语写一篇短文投稿，谈谈你是怎样理解低碳生活的，并描述你在日常生活中实现低碳生活的具体做法。 

 提示词语：protect, recycle, reduce, environment, energy  

 提示问题： 

 ● What do you think of low-carbon life? 

 ● What do you do to have a low-carbon life? 

 An idol is someone who we respect or love. However, unlike many of my classmates, my idol is not a film star, a famous writer or a sportsman. He is neither a world leader nor an important person from history. My idol is my dad. 

 Most people believe that a man should go out and work. However, when I was only a five-year-old boy, I was seriously ill and needed attention all the time. My mother and father both worked and my grandparents lived far away. This was a big problem. My dad knew how much my mum loved her job, so he stopped working to stay at home and look after me. Many men in this situation would want their wives to stay with the child, but my dad always thinks about others before himself. This made me start to respect him. 

 My dad later took a job and worked at night. He chose the job so that he would only be out of the house when I was sleeping. Since then, my dad has helped and supported me in everything I do. I remember when I was learning to ride a bike. My dad ran behind me and held the back of the bicycle so that I would not fall. I felt so safe because I knew he was near. I did not notice when he stopped holding me. Soon, I was able to ride by myself. 

 My family is not rich, and we do not own a big house or an expensive car. My dad has showed me that something is more important than money. My dad gives me his time. Although he now works hard every day and is often very busy, he always makes time to stay with me. He helps me with my homework, and plays games with me at weekends. We make and fly our own kites, go for walks in the countryside, and even cook together. He taught me that I can achieve anything if I really work hard on it. 

 My dad is my idol because he showed me the most important things in life. 

 With most people staying at home because of COVID-19 (新冠), live streaming (直播) has become more and more popular. It is not only fun and interesting, but has also provided a new stage (舞台) for traditional culture artists. 

 On video sites and apps such as Douyin and Bilibili,  Some of them sing Peking Opera, some show their hand-made products, while others perform traditional Chinese music. 

Li Jun is a laosheng (old male role) Peking Opera performer with the Shanghai Jingju Theater Company. During the outbreak (疫情), Unlike performing on a normal stage, Li uses everyday places as his stage, including his backyard, and even the kitchen. Besides singing, Li also teaches viewers (观众) about Peking Opera in a humorous way. People can ask him questions and get answers directly. "Live streaming has brought this elegant (高雅的) art down to earth," one viewer (观众) said. " " Up to now Li has more than 6,000 fans on Douyin, while one of his videos has received 42,000 views on Bilibili.

 Other kinds of artists also see live streaming as a new chance. On March 26th, the third China Huafu Day, Bilibili live streamed a fashion show. including those from the Wei (220—265), Tang (618—907) and Ming (1368—1644) dynasties. During the show, viewers not only enjoyed seeing the clothes but also watching how performers use ancient styles of make-up. For example, one blogger (博主) taught people how to draw the guiye eyebrow (桂叶眉) which was a typical make-up style during the Tang Dynasty. 

 As Guangming Daily noted,  

 A．Some famous artists perform traditional Chinese music through this special way. 

 B．live streaming has created a new way in which traditional culture can be kept alive. 

 C．Performers presented beautiful clothes in traditional Chinese styles, 

 D．many traditional artists are trying live streaming for the first time. 

 E．It allows young people to get closer to this traditional art and learn more about it. 

 F．In this way, viewers can enjoy different kinds of beautiful clothes. 

 G．the 59-year-old artist started live streaming for the first time. 

 Awe is the feeling of amazement and respect mixed with surprise. Research shows that awe experiences decrease stress and anxiety and increase positive (积极的) emotions and overall satisfaction in life. It can also improve our relationships, making us more likely to help others and more supported. 

 Most of us connect awe with something unusual and beautiful: nature, music or a spiritual experience. But ordinary people can bring about awe too. Research shows we can be awed by our nearest and dearest—the people sitting next to us, or talking on the other end of the phone. Psychologists call this interpersonal awe. 

Often, this interpersonal awe is how people respond (反应) to life's big changes, like seeing a baby's first steps or a friend fighting against cancer. Yet interpersonal awe happens in our everyday life, too. John Bargh, a psychologist, said he was "truly awe struck" by his then 5-year-old daughter while dining in a McDonald's years ago. When she heard another child crying across the restaurant, she took the toy from her Happy Meal, walked over and handed it to him.

We can't make someone else behave in an awesome way, but we can get prepared to notice it when they do and take steps to strengthen the emotion's positive effects.

To increase your chances of feeling awed by people around you, Marianna Craziosi, an expert in positive psychology, suggests you direct your attention to people's positive sides and catch them at their best. You may think your brother or friend is selfish; there may be a little truth to that, but it's never the whole story. "Try to find examples of him helping others or doing something great. In other words, become a field scientist, like Jane Goodall," Graziosi said.

To help you recognize and remember a special experience, say out loud "Wow, that was awesome!" when awe strikes you. Enjoy it in the moment and tell others about it. This will strengthen your positive emotions. And recall it or write about it later. Studies show awe can be drawn again simply by remembering an awe experience.

When you feel awed by people around you, thank them and let them know just how much their actions affect you. This makes the other person feel good and can give your relationship an improvement. And you'll also have high levels of happiness and psychological well-being.

 Awe could be anywhere. Perhaps awe, while an ordinary response to the extraordinary, is also an extraordinary response to the ordinary. 

While the pandemic（流行病） has prevented people from traveling afar, there's a silver lining in that dark cloud: micro-tourism, or mini-vacations.

 Micro-tourism refers to short-distance（短距离） travel in which people drive two or three hours to a nearby place and spend two or three days there. Instead of requiring a plan with lots of details and money, micro-tourism allows travelling to be simpler and less expensive.  

 According to China Daily, micro-tourism began catching on about seven years ago. With the pandemic prevention making long trips less convenient, more and more people choose to take short trips instead.  

 Mark Hou from Beijing is one of them. Before the pandemic, he preferred taking long trips abroad or visiting other places in China. But the pandemic meant he had to adapt（适应） to a new travel style.  

"Traveling a long distance means you should take public transportation, like planes. But that would be likely to increase the chances of infection （感染）," Hou said. "To stay healthy, short-distance travel is the better choice." But that doesn't mean Hou has lost fun during his short trips.

After a long and tiring week at work, Hou likes to invite friends and drive to the countryside near Beijing on weekends. "Walking in the mountains or having a hot spring, we can get the fresh air and have some exercise," Hou explained. "That can really move the stress out of our daily life."

 To meet the new needs, many cities have also created more chances for tourists. For example, Shanghai started a number of micro-tourism products for half-day and one-day tours, including exploring cultural heritage（遗产）sites in the city and experiencing country life.  

"With these programs, young tourists no longer look to get ‘distance', but are willing to find new ways to experience their cities," Feng Rao, head of a tourism research center, told People's Daily. Travel doesn't mean you need to go far away to find a place to relax. That's also the aim of the micro-tourism.

 On 20 July 1969, the world celebrated an important moment in history when American astronaut, Neil Armstrong, became the first man to walk on the moon, making a giant leap for humanity. For more than 50 years, human beings have tried many times to understand the space environment. These efforts have paid off. Today, we are in a better position to understand our universe in which we live, thanks to space exploration.  

 Space exploration has triggered advances in science and technology which have benefitted humans and improved the quality of life on Earth. These benefits are related to space technology such as satellite communications, global positioning system(GPS) and weather forecasting. The development of satellite technology, for instance, makes telecommunications possible, connecting people from different parts of the world through satellite television, phones, radio and Internet access. Today, space technology also enables us to have virtual (虚拟的) meetings and lessons, making work and study from home possible during the Covid-19 pandemic.  

 With the excitement and curiosity generated (产生), space exploration is attracting young people to careers in engineering, science, technology and mathematics, which creates innovations (创新) in science and technology. In countries such as America, Canada and Europe, space exploration has also generated jobs in fields related to engineering, technology and science. Even if interested youngsters do not end up in a job in these areas, space technology enriches their imagination about the possibility of life beyond Earth and space travel. To this end, space exploration continues to encourage human imagination, inspiring (激励) people to write stories and create movies, photographs and songs about space exploration.  

 Although there are many benefits, space exploration has often been criticized (批评)for its high cost. According to the University of Florida, it costs about $500 million to launch (发射) a space shuttle and many argue that this money could be better spent on solving the problems on Earth such as hunger, pollution, diseases and climate change. Although space exploration cannot directly provide immediate solutions to these problems, it generates many useful technologies and new knowledge in sciences necessary to improve the conditions of human life on Earth.  

 Every year, about a thousand innovations in the space programmes find their way into earthly technology that leads to better farming; better medical instruments; and more energy-efficient vehicles(交通工具). As a result, the money spent on space exploration does finally benefit human beings.  

 There is no doubt that space exploration has produced many benefits for humanity. It has also encouraged many to understand Earth and the universe in a deeper way. In the coming decade, we can continue to expect more exciting discoveries. We may eventually even find another planet where humans can live. 

 This was our last trip before high school. I had been looking forward to it for weeks. But at the roller coaster, my stomach felt too tight to say anything at all. 

The big girl beside us was Tasha, my best friend Dan's sister. She was a singer. She was fantastic on the stage. Just the image of her up there made me think she was so cool.

Our roller coaster car pulled up, and my friends rushed forward, I felt my legs couldn't move. All I could think about was the roller coaster might fly off into the sky. Without a word, I turned, ran out of the line. I knew what people were saying about me, but I didn't care. I just kept moving past the crowd, found a bench ( 长椅 ) near the bathrooms to sit down and put my head in my hands.

"Hey! Steve! Are you okay? " I looked up. It was Tasha!

"Oh, uh, yeah, I just started feeling, um, sick." I responded.

"You know, it's okay if you were scared. Everyone gets scared." She said.

"You don't." I said in a low voice. "I've seen you on that stage. You were fearless."

"I'm glad it looks like I'm not scared!" Tasha smiled. "But that's not true. I get really scared and nervous before I perform."

 Before I noticed she was on the bench by my side, her words moved on. 

"Hey, look, singing is important to me. And I want to share what I love with my people. So, even if I'm scared. I do it anyway. I push through the fear and just get up and do it. Is taking roller coaster important to you?"

"Yeah, it is. And I want to be able to look back and remember having fun with my friends. I don't want to remember running away and sitting alone by the bathrooms."

"Everyone gets scared, but brave people don't let fear control them." She looked into my eyes. Still being lost in what she said, I saw my friends coming towards me.

 I got up and went with them to the coaster. 

 When we were leaving, Tasha took a photo of my big smile in front of the coaster. I put it on my door. It stayed there through all four years of my high school, a reminder of what was more important to me than fear. 

It was almost midnight, but Mary couldn't fall asleep. "One sheep, two sheep…" She (start) to count sheep. But did it really work? Actually, some (scientist) believe this may not be a very good way to fall asleep. Some people try so hard to count that they can be more clear-headed. Instead, they can try taking a bath to fall asleep. They can also think about a quiet beach or a walk in the woods, can make them relaxed and fall asleep more (quick).

 【参考答案】 

 Today, dogs are found  (help) to all who fly in airplanes. They are trained to smell, track, and find bombs on planes and in luggage. Dogs are easy to train because they already have deep connection to humans. Many of these dogs are donated to the safety program, where they (give) a good home. The partnership between dogs and humans allows each to profit from the special talents of the other as they work together （save）lives. 

Hangzhou is one of China's most popular cities. It is full of cultural heritage(遗产) and famous its natural scenery. Italian traveller Marco Polo described Hangzhou as the (fine) and most splendid city in the world. The beauty of West Lake has inspired countless poets and painters, and you can't leave without (try) the Longjing Shrimp, one of Hangzhou's signature dishes. The dynamic city is home to many of China's tech companies including e-commerce giant Alibaba.

Mark Levine, who is 74 years old, has been living in China for 17 years. He is an American 1  and song writer. He has written more than 80 songs, most of which are inspired by his true 2  in China.

Mark is now an educator at the Minzu University of China. About half of the students come from one of the 55 Chinese minorities(少数民族). Most of the time, through his students, he learns about their 3 traditions. "I am here as a teacher, but I think my students have taught me as much as I have taught them," Mark said.

Mark has traveled to many parts of China and seen some 4  in China over these years. He clearly remembers his first long-distance trip in China. It 5  him a few hours by plane and then two hours by car before reaching his destination(目的地). But nowadays, 6  the high-speed railway and highways, he can reach the same destination within two hours.

China's electronic payment and sharing bicycles have given people a 7 life. However, when asked about the biggest change, he said that must be the increase of confidence in students. When he first arrived in China, a lot of students were very shy and they were unsure 8 their future. But now to his 9 , they are confident to share their views about China and foreign countries.

"You can always find things that you're not expecting and discover new things that you're able to learn. That's perhaps the most 10 thing about being in China," said Mark.

Pumpkin(南瓜)carving at Halloween is a family tradition. We visit a local farm every October. In the pumpkin field, I compete with my three brothers and sister to seek out the biggest pumpkin. My dad has a rule that we have to carry our pumpkins back home, and as the eldest child I have an advantage — I carried an 85-pounder back last year.

This year, it was hard to tell whether my prize or the one chosen by my 14-year-old brother, Jason, was the winner. Unfortunately we forgot to weigh them before taking out their insides, but I was determined to prove my point. All of us were hard at work at the kitchen table, with my mom filming the annual event. I'm unsure now why I thought forcing my head inside the pumpkin would settle the matter, but it seemed to make perfect sense at the time.

With the pumpkin resting on the table, hole uppermost, I bent over and pressed my head against the opening. At first I got jammed just above my eyes and then, as I went on with my task, unwilling to quit, my nose briefly prevented entry. Finally I managed to put my whole head into it, like a cork(软木塞)forced into a bottle. I was able to straighten up with the huge pumpkin resting on my shoulders.

My excitement was short-lived. The pumpkin was heavy. "I'm going to set it down, now," I said, and with Jason helping to support its weight, I bent back over the table to give it somewhere to rest. It was only when I tried to remove my head that I realized getting out was going to be less straightforward than getting in. When I pulled hard, my nose got in the way. I got into a panic as I pressed firmly against the table and moved my head around trying to find the right angle, but it was no use. "I can't get it out!" I shouted, my voice sounding unnaturally loud in the enclosed space.

注意：1. 所续写短文的词数应为150左右；2. 续写部分分为两段，每段的开头语已为你写好；

Paragraph 1：

I was stuck for five to six minutes though it felt much longer.

Paragraph 2：

That video was posted the day before Halloween.

A new branch of the Palace Museum is expected to rise on Beijing outskirts over the next few years to better showcase the  (museum) cultural relics. 

After nearly a decade of preparation, construction of the new branch  (begin) last December. Located in Xiyehe, a village in Haidian District, the new branch will cover more than 100, 000 square meters, including  exhibition space of over 60, 000 square meters for cultural relics and more than 35, 000 square meters for relic  (restore). 

At present, over 1. 86 million cultural relics  (house) in the museum. However, only about 10, 000 pieces are able to be displayed every year due to limited exhibition spaces  outdated offices. 

Du Haijiang, deputy director of the Palace Museum, briefed the public on the project in an interview with CCTV on January 26th, (explain) that calligraphy works and paintings couldn't be put on display during rainy seasons, in winter or summer, because of strict temperature and humidity requirements. Some silk and cotton artworks (current) cannot be exhibited at all for lack of the necessary environment.

On completion of the new branch, it will be possible  (display) between 20, 000 and 30, 000 individual relics each year. The new venue will be a modern exhibition space  multiple functions to provide relic preservation, repair work, and visitor services. 

When I was in sixth grade, I joined the band program to learn to play the clarinet (单簧管). The beginning of the year had gone 1 . But as most students progressed, I seemed to fall behind. One day, when my teacher told us to play in front of the other students. I was filled with fear. I knew I would 2 . When I began to play, my rhythms (节奏) were good, but my tone was another 3 . "Did you practice your lesson?" the teacher barked at me. I felt so ashamed and my world came 4 down in an instant.

From then on, I hated playing the clarinet and I kept getting 5 . With the day of the new performance approaching, I grew increasingly upset. In a moment of 6 , I asked for sick leave. It was so relieving and such a(n) easy way out. 

The avoidance of my lessons continued until my mum asked me about it. "I want to quit." My tears started 7 . "If you really want to quit, why are you crying?" asked Mum. She 8 and I realized I wanted to stay in band and, by not facing my fears, I had created a black hole that would be difficult to 9 out of. I made a resolution not to hide from my fears and to stand up to even the worst of them, so a 10 could be achieved.

The next day I met with my band teacher and told her I was having a problem and couldn't 11 why. She asked me gently to play for her. I tried, but only an unpleasant sound came out. She didn't shout at me and handed me a new reed (簧片). I put it in place and tried again. To my great 12 I could play well. My problem was solved and my fear was 13 a lot that year.

Looking back I'm glad that I overcame my fear. Fear can 14 everything in a person's life. Hiding from those very fears only creates a hole, which makes a person stay 15 inside. After facing up to a fear, one may find life easier and much more enjoyable.

Pets should not be left alone for too long during the day. But our busy lifestyles will sometimes tear us away.  Here are some tips to keep your pets content. 

Cats don't simply curl up and sleep when you leave. If they have a friend or sibling they will create games and comfort one another but if they are alone they will need more stimuli (刺激物). Leaving the TV or radio on can help, and while you work out their favorite channel, you can't go far wrong with classical music.

They will keep your cat physically and mentally busy, which will lessen the separation anxiety. Some of the toys are also practical for your home, such as scratching posts to prevent the furniture from being scratched. 

It's not just cats that suffer from separation anxiety Dogs also dislike being left alone and unfortunately they can't tell whether it's been ten minutes or ten hours: the displeasure felt is very similar.

Background noise from the TV or radio can help them to feel less alone. There is even a dog TV channel designed to create happy and calm thoughts in dogs, showing idyllic scenes of fields, beaches and other dogs. 

You can also gradually lengthen the distance and time of your separation until your dogs can be left alone for 20 minutes without showing their usual symptoms of sadness and stress.

A. A number of cat toys are also helpful.

B. Schedule daily play sessions with your cats.

C. But you can help ease the negative feeling at least.

D. That creates a lot of guilt and worry for their well-being.

E. In this way, they can disassociate your absence with negativity.

F. They need stimulation for the period when they will be left alone.

G. Over time, they will look forward to their separation to get a reward.

People may wonder after using up Earth entirely, where are we going?

The most common target is our neighbour Mars. It is about half the size of Earth. From an astronomer's perspective, Mars is Earth's identical twin. And Mars has been in the news a lot lately, promoted as a possible homeland for humanity in the near future. While human-led missions to Mars seem likely in the coming decades, what are our prospects of long-term habitation on Mars? Present-day Mars is a cold, dry world with a very thin atmosphere. Its average surface pressure is less than 1 per cent of Earth's. Surviving without a pressure suit in such an environment is impossible. The surface temperature ranges from 30℃ in the summer, down to-140℃ in the winter; these extreme temperature changes are due to the thin atmosphere on Mars.

Despite these clear challenges proposals for changing Mars into a world suitable for long-term human habitation abound(大量出现).Mars is further from the Sun than Earth，so it would require significantly more greenhouse gases to achieve a temperature similar to Earth's. Thickening the atmosphere by releasing CO2 in the Martian surface is the most popular "solution" to the thin atmosphere on Mars. However, every suggested method of releasing the carbon stored in Mars requires technology and resources far beyond what we are currently capable of. What's more, a recent NASA study determined that there isn't even enough CO2 on Mars to warm it sufficiently.

Even if we could find enough CO₂, we would still be left with an atmosphere we couldn't breathe. Earth's atmosphere contains only 0.04 per cent CO_2, and we cannot tolerate an atmosphere high in CO₂. For an atmosphere with Earth's atmospheric pressure, CO₂ levels as high as 1 per cent can cause sleepiness in humans, and once we reach levels of 10 per cent CO₂, we will suffocate even if there is abundant oxygen. The proposed absolute best-case scenario (设 想)for changing Mars leaves us with an atmosphere we are incapable of breathing.

Living on a warming Earth presents many challenges. Scientists study Mars and other planets to better understand ourselves. In searching the universe, we are not looking for an escape to our problems: Earth is our unique and only home in the universe. There is no planet B.