细节理解题 知识点题库

    There is such a group of singers in the western musical circle at present, who enter the business as online celebrities(名人) and then become top idols and giant stars globally. They become popular for their videos online and then they are discovered by talent agents and gradually cause huge storms in the musical circle. For example, Troye Sivan, a singer who is nicknamed "chuoye", became popular on Youtube from an early age.

    As a popular video sharing website, YouTube has given rise to plenty of stars, creating a new celebrity culture. Providing a platform where anyone can post videos, Youtube presents the opportunity for anyone to achieve fame by simply uploading a short video. Sivan has been making Youtube videos since he was 12 to show his singing talent. In the digital age, Sivan has already developed large devoted audience online and his sensitive video blogs have earned him extreme popularity.

    A survey has showed that US teenagers are more attracted with YouTube stars, which is a surprising result. YouTube stars are judged to be more attractive, outstanding and related than traditional stars. Looking at the survey comments and feedback, teens enjoy a close and real experience with YouTube celebrities, who aren't carefully directed by design. Teens also say they appreciate YouTube stars sense of humor and risk-taking spirit, which are often limited by Hollywood stars. As a result, singers who make their first show in the traditional way no longer have a complete advantage in front of the audience. Online platforms open up a lot of doors for people. They become the best place to be discovered.

    Birthday parties and graduations are occasions when people celebrate with balloons, often releasing (释放) them into the sky happily. But what happens to those plastic balloons once they become flat? Where do they end up?

    For years, many environmental groups have pushed for mass balloon releases to be inhibited, saying that balloon pieces and strings are dangerous to wildlife. "They can bring harm to wildlife simply because they are colorful and bright, so wildlife might think they are delicious food, and their bodies can get caught by the strings, thus making it difficult for them to swim or breathe." Emma Tonge, communications and outreach specialist at the National Oceanic and Atmospheric Administration, told USA Today. Yet releases still happen.

    Researchers in Australia analyzed the effects that soft plastics like balloons have on seabirds. They have discovered that soft plastics are more likely than hard plastics to cause barriers in seabirds' gastrointestinal tracts (胃肠道). Of the birds examined  nearly one out of five died as a result of swallowing a balloon or balloon pieces.

    "If seabirds eat plastics, their risk of death increases, and even a single piece can be deadly," wrote lead study author Lauren Roman, PhD student at University of Tasmania. "The evidence is clear that if we want to stop seabirds from dying from plastic ingestion (吸入) we need to reduce or remove marine debris (海洋垃圾) from their environment, particularly balloons."

    Balloons Blow, a nonprofit organization, is devoted to educating people about the dangers released balloons can have on animals, people and the environment. The group points out that all released balloons return to the ground as litter. Animals like birds, whales and sea turtles can die after swallowing balloons.

    Summer is here, and with it comes a chance you'll get too much sun. While there's no cure for sunburn, a small but fascinating new study suggests taking large amounts of vitamin D after exposure may prevent the associated redness and inflammation (发炎) .

    In the paper, researchers exposed 20 volunteers to a light resembling solar radiation to induce a sunburn on a small piece of skin. They then gave the ''burn victims'' large amounts of vitamin D, and followed up with participants one, two and three days (and a week) later to measure skin redness and thickness. The researchers found that vitamin D decreased inflammation and redness, compared with taking a placebo (安慰剂) . And this effect increased in proportion to how much was consumed. Vitamin D also appears to increase the activity of a gene called arginase-1, which is involved in tissue repair and healing. Taking 50, 000 international units (IU) of vitamin D--125 times the recommended daily allowance-led to a significant reduction in redness and inflammation, compared with the placebo. Those who took 100,000 IU had even less redness and pain; and those who took 200, 000 IU had the greatest reduction in inflammation.

    This is the first study to show vitamin D can reduce inflammation, and suggests that it ''could potentially help prevent sunburn, '' says senior author Kurt Lu, a physician scientist and assistant professor at Case Western Reserve University.

    It used to be thought vitamin D was primarily involved in building healthy bones and muscles, but recent research has found it has many more roles, including influencing inflammation, such as the kind associated with sunburns.

    So, if you get burned, should you take a lot of vitamin D? The study authors don't recommend it. ''I think that's probably not a good idea and not well established by this study, '' says Barbara Gilchrest, a physician scientist at Massachusetts General Hospital. Such large amounts, if taken repeatedly, have the potential to cause vitamin D toxicity (毒性) .

    Nao, the first robot able to show feelings, has been created by a European research team. When Nao is sad, he lowers his head and looks down. When he's happy, he raises his arms for a hug. Nothing is out of the ordinary, except that Nao is a robot.

    "We're modeling the first years of life," says Lola Canamero, a computer scientist at the University of Hertforshire. "The feelings are shown through physical gestures and body movements rather than facial or verbal (言语的) expressions."

    In the future, says the scientist, robots are likely to act as companions, provide support for old people, and help people shop online. In such uses, the display of feeling will be important in making the interactions (交往) more natural and comfortable.

    Nao has been programmed to copy the emotional skills of a one-year-old child. It can memorize faces, and knows the basic rules of good and bad. Based on these it can decide how to react to what is going on. The actions going with each feeling are pre-programmed, but Nao decides for itself when to display them.

    Nao is also programmed to have different personalities. A more independent robot is less likely to call for help when exploring a room, while a more fearful robot will show distress if it finds something in the room that may be harmful.

    Canamero's team will take its emotional programming forward into medical applications. Part of the project will look at ways to use robots in hospitals to support the roles of doctors, nurses and parents. Children might find that a small, friendly-looking robot that can understand their emotional states makes them less anxious. "We want to explore different roles—the robots will help the children to understand their treatment and explain what they have to do. We want to help the children to control their anxiety." she says.

The ex-wife murder

    "Who shot her?" cried Mr. Rogers as he rushed into the hospital three minutes after his ex-wife died from a gunshot through her head.

    "Just a minute, Mr. Rogers," said Detective Timo. "We'll have to ask you a few questions first. Although you have been divorced for the past six months, you still live in the same house with your ex-wife, Mary Ann, right?"

    "That's right," replied Mr. Rogers.

    "Did you have trouble recently?"

    "Well… yesterday, when I told her I was going on a business trip, she threatened to kill herself. I had to take a bottle of iodine (碘酒) quickly from her hands because she was about to drink it. When I left last night at seven, I told her I was spending the night with friends in Sewickley. She didn't argue. And I got back to town this afternoon," continued Mr. Rogers. "I called home and the maid answered."

    "Just what did she say?" asked Detective Timo.

    "She said,' Oh, Mr. Rogers, they took the poor mistress to St. Ann's Hospital about half an hour ago. Please hurry to her.' She was crying, so I couldn't get anything else out of her. Then I hurried here. Where is she?"

    "The nurse will show you," said Detective Timo with a nod.

    "A strange case," said the police. "This couple is a little too much for me! A man and a woman living together after being divorced six months!"

    "Did anyone tell Mr. Rogers that Mary Ann died from a gunshot before he arrived?" asked Detective Timo, deep in thought.

    "Nobody did. I ordered everyone who knows the details of the case not to discuss it."

    "That's the point. You'd better detain (拘留) Mr. Rogers. If he didn't shoot her himself, I'm sure he knows who did."

When I tell people I wrote a book with my dad, they usually say, "It must be nice to think of the legacy (遗产) you created with someone who means 90 much to you."

This was a beautiful idea, but it was not the way I, or my dad, ever thought about the cooperation. Though we created something we are proud of, "nice" is not the word either of us uses to describe the process.

"It was more confrontation (对抗) than cooperation," my dad likes to say. I agree.

When we landed a book deal, we began a wring journey that was more difficult than either of us had expected, but also far more rewarding.

For almost three years, we met once or twice a week at my parents' house and talked daily about the plan and the outline of each chapter. After the meeting, one of would write a rough draft that the other would build on. I wanted the book to focus on positive vices (不良习惯): such as moderate (适度的) chocolate. However, my dad felt the book should include chapters dealing with things like walking and sending tine with family Finally, I saw it his way. He said the book was about more than just good advices. It was about encouraging people to enjoy life in healthy ways.

Writing this book was a reminder that our family members share not only our faults but also our strengths. My dad is smart, funny, critical and caring. He has a strong passion for the truth. I hope I share these great qualities. For this book, he researched each topic with an enthusiasm 1 had never seen from him, and he insisted that we constantly question and critically analyze every piece of information-even our own conclusions. He was determined to cooperate on a book, not because he could not write one on his own, but because he believed that we could create something better together than we could alone.

I am not sure if our cooperation led to better writing, but it led to a better writing experience. Writing this book was difficult, sometimes more difficult than past projects, but it was never lonely.

The last few days before Christmas passed quickly and it was soon Christmas Eve. That night when everyone went to bed, Bunny couldn't sleep. He still couldn't think of what he wanted his Christmas gift to be. He wondered how Father Christmas would know what to bring him if he didn't know himself.

As he was sitting up in bed, Bunny heard a big noise on the roof (屋顶) and a sound downstairs. It was Father Christmas, he realized. Bunny jumped out of bed and raced down the hall to the stairs hoping to have a look at the old man with his own eyes.

By the time Bunny reached the bottom of the stairs, though, everything was again silent. Beautiful gifts were piled (堆积) under the Christmas tree, but Father Christmas was gone. He looked for him for a few minutes, but it was already too late. Bunny turned to climb back upstairs when he heard a cry.

"Hello," said Bunny. "Is anybody there? "

He was answered by another cry. Bunny looked around the big pile of gifts to see what was making the noise. Right under the tree was a funny looking brown animal with big feet and sad eyes. Bunny might have mistaken it for a dog, if it hadn't been for the antlers (鹿角) on its head.

"Are you a reindeer (驯鹿)?" asked Bunny.

"Yes," replied the animal. "My name is Ralph."

"And you were pulling Father Christmas's sled (雪橇)?"

"I was until I got airsick (晕机), " replied Ralph. "I'm afraid I wasn't cut out for the job. Now I'm stuck here and I don't know how to get back to the North Pole."

"Well, if you like, yon can stay with us as a friend," said Bunny. As he made the offer, Bunny suddenly realized the gift he wanted from Father Christmas was a new friend!

Imagine reading a story titled "Pursuing Success." That would be an inspiring story, wouldn't it? Maybe—but maybe not. It might well be the story of someone whose never-ending chase for more and more success leaves them unsatisfied and incapable of happiness.

Though it isn't a conventional medical addiction, for many people success has addictive properties. Obviously, success goes with praise. To a certain extent, praise stimulates the neurotransmitter dopamine (神经递质多巴胺), which contributes to all addictive behaviors.

The desire for success may be born to human nature, but specialness doesn't come cheap. Success is tough work, and it requires bearing the cost of losing. In the 1980s, the physician Robert Goldman famously found that more than half of ambitious athletes would be willing to take a drug that would kill them in five years in exchange for winning every competition they entered.

Unfortunately, success is endless. The goal can't be satisfied; most people never feel "successful" enough. The high only lasts a day or two, and then it's on to the next goal. Psychologists call this the hedonic treadmill (快乐跑步机现象), in which satisfaction wears off almost immediately and we must run on to the next reward to avoid the feeling of falling behind.

People should get off the treadmill. But quitting isn't easy for addicts. For people hooked on substances, withdrawal can be a painful experience, both physically and psychologically, research finds that depression and anxiety are common among outstanding athletes after their careers end. Olympic athletes, in particular, suffer from the" post-Olympic blues."

Just like wine, success in and of itself is not a bad thing. Both can bring fun and sweetness to life. But both become bossy when they are a substitute for — instead of a complement (补充物)to — the relationships and love that should be at the center of our lives.

Your best friend that follows you around when the sun comes out - your shadow - doesn't serve an important function like your heart or brain, but what if you could use shadows to create electricity? When using solar panels (电池板) that are powered by light, shadows can be boring because it means electricity can't be created. However, researchers from the National University of Singapore have engineered a way to create power from the shadows present everywhere.

A team of the university created a machine that can collect energy from shadows. It is created by placing a thin coating of gold onto silicon (硅). Like in a normal solar panel, when put in light, the silicon electrons (电子) become energized and the energized electrons then jump from the silicon to the gold. The voltage (电压) of the part of the machine that is placed in the light increases relative to the dark part and the electrons in the machine flow from high to low voltage. They are sent through an external circuit (外电路) creating a current that can be used to power another machine. The greater the contrast between light and dark, more energy is provided by the machine.

The team is working on improving the performance of the machine, borrowing approaches from solar panels to gather light. Increasing the amount of light the machines can receive allows them to better make use of shadows, as well as developing shadow energy collecting panels that can successfully gather from indoor lighting. The team is also researching the use of other materials other than gold to drop the price of the machine, meaning they would be more cost effective and easier to apply in society.

Shadows are present everywhere and perhaps one day in the future we will be able to collect energy from them by placing the shadow-effect energy machine around the world in places that have been considered unfit for solar panels to work, or indoors. "A lot of people think that shadows are useless," Tan says, but "anything can be useful, even shadows."

Jack Frost has paid another visit to the Midwest. For the second time this week, a major winter storm has left people from Oklahoma to the Great Lakes struggling to stay safe and warm. Heavy, wet snow has shut down major highways, put off flights and left hundreds of thousands of Midwesterner without power. "It's just snow. That's all we can see," said Shannon Wick ware of Woodward.

The storm began in Texas on Sunday and rapidly traveled north. A gust of wind pushed the storm up towards Oklahoma, bringing fifteen inches of snow to parts of Oklahoma. It then moved east and hovered over Chicago, dropping four inches of wet snow on top of the city and its suburbs. Airlines canceled nearly 500 flights at Chicago's O' Hare and Midway airports. Later, the storm swept Ohio, causing a lot of problems for the local people. Taking into account the safety of their students in the storm, many schools in the affected areas either put off opening or did not open at all.

In Kansas City, Missouri, up to ten inches of snow had fallen before midday on Tuesday. The city's mayor, Sty James, declared a state of emergency. Most government and office buildings were shut down. Some hospitals were forced to close urgent-care clinics.

While heavy snowfall is not usual for this part of the country at this time of year, it is the amount of moisture in the snow that makes conditions extra "treacherous". When snow is especially wet, it weighs down trees and brings down power lines. Roofs can cave in under the pressure and roads can become very icy. The power lines have cut off electricity to more than 100, 000 homes and businesses in the Midwest.

As snow falls and the temperature continues to drop, people are preparing the best they can to stay dry and safe. The bad weather is making travel difficult for even snowplows (扫雪机) and repair vehicles.

The Best UK Festivals of 2020

We've picked this year's best UK festivals—find your favourite and get out there this summer.

All Points East

Returning for a third year after its successful 2018 launch, All Points East is a general 10-day festival that takes over Victoria Park in late May. The opening and closing three-day weekends are given over to music.

Place: Victoria Park

Time: May 22, 2020-May 31, 2020

Ticket: Adult￡35; Age19-24 with ID￡28;Under18 years old, free

Isle of Wight

Huge headliners is one of the UK's biggest rock festivals. Now in its 52nd year, the modern-day Isle of Wight festival is a far cry from the hippy(嬉皮士) love-in that landed back in 1968. Nowadays, big-name headliners and commercial rock and pop favorites are the order of the day.

Place: Seaclose Park, Newport

Time: Jun 13-14. 12:00 a. m. -15:00 p. m.

Tickets:￡25 Adult;￡15  Age19-24 with ID; ￡10 under 12 years old, under7, free

Love box

Consistently one of the finest festivals in London, catering for cool kids and party monsters alike, Love box has expanded again to become a three-day event in 2020. This year will be its second in west London's Gunnersbury Park.

Place: London's Gunnersbury Park

Time: July12-14. 1:30 p. m. -2:30 p. m.

Tickets:￡185(adult three-day weekend);￡70(adult day ticket)

Junction 2

Calling all technology heads: in 2020, this big festival is spreading out over two days again following last year's successful expansion. Junction 2 is a meeting of some pretty serious music minds.

Place: Boston Manor Park

Time: July 15-16

Tickets:￡45 for all ages

There you are in your favorite clothing store. You don't really need to buy anything, but everything is so cheap and stylish! Before you know it, you leave the store with bags and bags of new clothes.

On the surface, this doesn't seem so bad. However, there are a lot of hidden costs behind the cheap price tags (标牌). To put it plainly, the fashion industry is terrible for the planet. Not only does it use up a lot of resources, but it also heavily pollutes the environment with chemicals, microplastics and unwanted waste.

Fashion is one of the least sustainable industries on the planet, commented Michael Stanley-Jones. "We've all become our own waste managers, hoarding fashion waste in our houses,” he noted.

It doesn't just take up space in our cupboards, though. It also ends up in landfills(垃圾场), too. But, thankfully, the fashion trend tides are changing. People are increasingly examining their own consumption and what changes they can make to become sustainable, Jane Fellner, founder and CEO of sustainable fashion seller Loopster, told the Guardian.

In particular, with its typically lower prices and rare fashion finds, shopping secondhand  has become an increasingly popular and eco-friendly option. According to online reseller ThredUp, the secondhand market is predicted to reach $80 billion by 2029. And, although fast fashion will continue to grow 20 percent over the next 10 years, secondhand fashion is expected to grow an unbelievable 185 percent in that same amount of time. Fellner continued: "Secondhand has become more socially acceptable. Thrifting ( 节约) is now massive on TikTok.”

The only true sustainable way to shop is to not shop at all, unless you're buying clothes that already exist.

Around the World by Wheelchair

Rick Hansen was always an active kid and loved to fish. When returning in a truck one day from a fishing trip, he had an accident and suffered injuries to his spine (脊柱). This 15-year-old young man awoke to find that he had lost the use of his legs. However, he didn't give up. Many months later he began to compete in wheelchair sports. At the age of 27, he decided to wheel around the world to raise awareness and money for spinal cord research. His tour took him through 34 countries around the world between 1985 and 1987.In this Man of Motion World Tour, he wheeled 24,901 .55 miles, which is equal to the distance around the earth.

Bad weather and difficult, rocky roads often provided challenges for Rick, but he continued to push himself to complete the trip. He was determined to succeed. Even mountains did not stop Rick Hansen. He wheeled himself up the Rocky Mountains and several other major mountains in the world. He even wheeled himself along the Great Wall of China!

"Never Give Up On Your Dreams" was his motto and he hasn't given up yet. He completed his world tour raising $24 million. He continues to work to increase knowledge of spinal cord injury. He is a true Canadian hero who shows what determination can achieve.

In the middle of the 19th century, a fever dream of riches beyond measure drew countless explorers west to the mountains of central California. Although the gold rush ended up being a bust for many who sought a fortune, some of those explorers discovered a natural treasure that would draw permanent settlers to Yosemite Valley in the following decade.

Vast wilderness, beautiful mountains, countless waterfalls, and abundant wildlife drew Native Americans to Yosemite roughly 10, 000 years ago. The first non-native tourists arrived in the mid-1850s after reports from gold seekers told of an area of breathtaking beauty that no words were able to describe.

Fortunately, some of Yosemite's earliest settlers recognized that Yosemite's natural beauty and resources needed to be preserved for future generations. In the midst of the Civil War, President Abraham Lincoln signed a grant to protect Yosemite permanently, thus making it the nation's first land to be dedicated to recreation and setting the stage for what would become the national park system.

One of Yosemite's earliest ambassadors was Scottish-American naturalist and writer John Muir. After living in Yosemite for a few years, he helped define its proposed boundaries. He also wrote articles that helped lead to its official title as a National Park in 1890. He later co-founded the Sierra Club in 1892 to advocate for its continued preservation and protection.

Located on the western slope of the Sierra Nevada mountain range in central California, Yosemite National Park runs across nearly 748, 000 acres, almost 95％of which is wilderness. Around four million visitors come to Yosemite each year to camp, hike its miles of trails, climb its rock formations, and photograph its impressive sights. Are you ready to visit Yosemite National Park? Which of Yosemite's sights would you most like to experience?

To most of us, school means classes, teachers, schedules, grades, and tests. But for the children at Sudbury Valley School in Massachusetts, school is very different.

Firstly, there are no lessons. All the children, aged between 4 and 19, do whatever they want.

There are no teachers-only "staff members". The idea behind this is that you do not need to make children learn, because children want to learn anyway. "You do not need to say to a three-year-old child 'Go explore your environment. "You can't stop them!" says Daniel Greenberg, a founder of the school. "But if you make children do what you want all day, they will lose all taste for learning."

At Sudbury Valley School, you will allow children to talk, read, paint, cook, work on computers, study French, play the piano, climb trees or just run around. Two boys spent three years just fishing!

The other way that Sudbury Valley School is different is that the children can decide the rules.

Every week, there is a school meeting where both children and staff have one vote each —even the four-year-olds. They decide the school rules, how to spend the school budget, and even which staff they want and do not want any more.

When the school first opened in 1968, people said it would never work. But today, the school has 200 students, and 80% of its students go on to college. Even the two boys who went fishing all the time have successful careers today. One of them is a musician and the other is a computer scientist.

Becca was 6 when she was told she had cancer on Sept. 8, 2014. She clearly remembers the bad days of her 26 months of non­stop treatment. Luckily, Becca celebrated her final treatment on Nov. 13, 2016, and she has been cancer­free ever since. But she was thinking about what her life was like while experiencing treatment.

I was never able to do much, and that's what the kids lying in their hospital beds right now experience, asking their mom and dad, “When are we leaving? When can I play with my friends？” So I decided I have to help them.

In February, 2017 Becca came up with the idea for Knots and Arrows, a company that makes bracelets (手镯) out of swimsuit materials (泳衣布料). Part of the money made from each bracelet goes to the organizations that help people with cancer.

Becca created the company with her father, Gerhard Salmins. Gerhard Salmins once had cancer and already recovered from it. “I would be in the hospital sitting there crying and then my dad would come in and he would play games with me，” she said. “It made me forget about what I was going through. ” Becca said the name of the organization shows the motto (座右铭) she stuck to through her personal cancer journey.

Her organization has already given thousands of dollars to research organizations and families in need. Becca said she hopes her bracelets will make people remember that great things can result from small changes. “No matter what age you are, what you look like, how you act, you can make a difference！” she said.

In 1826, a Frenchman named Niepce needed pictures for his business. But he was not a good artist, so he invented a very simple camera. He put it in a window of his house and took a picture of his garden. That was the first photo.

The next important date in the history of photography (摄影) was in 1837. That year, Daguerre, another Frenchman, took a picture of his reading room. He used a new kind of camera in a different way. In his picture you could see everything very clearly, even the smallest thing. This kind of photo was called Daguerreotype.

Soon, other people began to use Daguerre's way. Travelers brought back wonderful photos from all around the world. People took pictures of famous buildings, cities and mountains.

In about 1840, photography was developed. Then photographers could take pictures of people and moving things. That was not simple. The photographers had to carry a lot of film and other machines. But this did not stop them, for example, some in the United States worked so hard. Mathew Brady was a famous American photographer. He took many pictures of great people. The pictures were unusual because they were very lifelike (栩栩如生的).

Photography also became a kind of art by the end of the 19th century. Some photos were not just copies of the real world. They showed ideas and feelings, like other art forms.

It had been a "long" and hard walk from home to the subway station for teenager Mandy Chan when she first put on hanfu in public. Chan is one of the founders of hanfu in Hong Kong. "It was a set with a cream-colored shirt, a brown jacket in China's Ming dynasty style and a red pleated(打褶的) skirt made by me," she recalled recently, almost 10 years later.

It was not the looks from others but her limited knowledge on the traditional Chinese clothing that had terrified her. Chan added, "If anyone had asked what I was wearing, or the history behind it, I would have been afraid I couldn't tell them the whole picture."

However, her uneasiness had gradually drifted away with more in-depth research on traditional Chinese culture. Hanfu was the traditional clothing of China's Han ethnic(民族的) group that was formed in the main residential areas of the Han people in ancient China. The historical clothing has untold stories and ideas in every detail. The cutting and stitching line in the middle part of hanfu fits the spine(脊椎) of the human body and helps people to dress properly. This design, which has transcended (超越) itself as mere decoration, points to the qualities of the wearers as upright(挺直的) and moderate (温和的) individuals.

"Instead of imitating people like what I used to do, I have jumped out of my comfort zone and found the style that suits me best," Chan said. "Through hanfu, I have found myself and so many unexplored things in my life." Chan added that she had found her lifelong passion through hanfu, which is a goal and dream that has never been absent from her life. Chan found she was not alone after falling in love with hanfu. She believes that classics will never go out of style and she herself has incorporated (使并入) hanfu into her everyday life.

What's a spacewalk? Any time an astronaut gets out of a spacecraft(航天器) while in space, it is called a spacewalk. Astronauts go on spacewalks for many reasons. For example, experiments can be placed on the outside of a spacecraft. This lets scientists learn how being in space af ects(影响) different things. By going on spacewalks, astronauts can also fix things instead of bringing them back to the earth to fix.

When astronauts go on spacewalks, they wear spacesuits to keep themselves safe. Inside spacesuits, astronauts have the oxygen(氧气) they need to breathe and the water they need to drink. To keep the astronauts and the spacecraft safe, the astronauts must leave and go back to the spacecraft through a special door. When on a spacewalk, astronauts use safety tethers to stay close to their spacecraft. Tethers are like ropes, connect the spacewalkers with the spacecraft. They keep astronauts from floating(漂浮) away into space. Another way astronauts stay safe during spacewalks is by wearing a SAFER. SAFER is worn like a backpack. It helps an astronaut move around in space.

How do astronauts train for spacewalks? One way is by going for a swim. Floating in space is a lot like floating in water. Astronauts practice spacewalks underwater in a huge special swimming pool. For every one hour they will spend on a spacewalk, astronauts need to train seven hours in the pool. Another way astronauts practice for a spacewalk is by using virtual reality(虚拟现实). It looks and feels just like a spacewalk.

Today, only three countries have finished spacewalks independently. They are Russia, the United States and China. The first person to go on a spacewalk in the world was Alexei Leonov from Russia. Zhai Zhigang is the first Chinese astronaut to go on a spacewalk. The world record of spacewalks is held by Russian astronaut Anatoly Solovyev. He has been on 16 spacewalks and spent more than 82 hours outside in space

I have dreamt of taking a trip to Hawaii since I graduated, but the best thing always needs waiting. I took a trip with my friends to Haleakala National Park, which lies in Hawaii.

When we arrived at Haleakala National Park, we were advised to watch the early morning sunrise. I was lost in the sightseeing that afternoon, so I could hardly wait to see the sunrise. In the next morning, we all got out of bed very early and got to the seaside at 3 o'clock. In the first half hour, we imagined how wonderful it would be when the first light came out through the thick clouds and how soft it would be when the light touched our skin, so we waited and waited. However, another half an hour later, I gradually lost my patience since there was nothing but the chilly darkness, and I felt that I was frozen to death. But my friends were still extremely cheerful.

Nearly another one hour later, "Amazing!" Judy burst out and we all shouted to welcome the light, which was really unbelievable. Until today, I dare say that it is the most impressive sunrise in my life. However, waiting in the morning darkness is also one memory I cannot wipe from my mind forever.

Waiting sometimes is really a hard thing for most of us as it needs patience and strong-willed determination, but what about the result after that? It might turn out to be pleasing, unbelievable and satisfying. So, it is really worthwhile to wait for the best.