① If you've ever seen alpacas (羊驼), you might just think they're fuzzy and cute. Now, it looks like this animal might be able to help scientists find a vaceine (疫苗) for COVID-19.
②In Australia, scientists are examining an unusual immunity (免疫) from alpacas that create two types of antibodies (抗体). Actually, the alpaca's unusual immune response had already been used in research for other viruses, such as HIV, around the world. Now the scientists have found that when alpacas are infected（感染) with COVID-19, their bodies react in a special way.
③"Alpacas and animals like them actually create two different types of antibodies. One is similar to the type humans make, but they also create things called nanobodies (纳米抗体)," said Michael James, a researcher who takes part in the study. The alpacas produced these nanobodies after researchers put a COVID-l9 viral spike protein (刺突蛋白) into their bodies. It is this protein that helps the virus infect our cells (细胞). The nanobodies, however, could stop infection from happening by blocking the protein.
④"You can think of our cells as a 'lock' and the viral spike protein as a 'key'," James explained. He said the nanobodies plug up the "lock" so that the "key"cannot get in.
⑤ Although the results look good so far, it will take some time to produce a vaccine based on the findings. The nanobodies require far more research to make sure they are both effective and safe. Since the nanobodi are newly found, they must be tested very strictly in the laboratory before they can be tried on human, according to James.
Many people dream of getting close to nature. But the thought of sleeping in a tent on the hard ground isn't very popular. RVs offer a great choice for those who want to experience the outdoors while still enjoying many comforts from home.
An RV, or recreational vehicle（房车）,is a motorhome or truck camper with sleeping accommodations inside. These travelling homes come in different sizes. shapes and prices. From nearly 14—meter motor homes that sleep up to 10 people to campers that sleep one or two, choices vary greatly. Therefore it is important that anyone wishing to rent or buy one reviews their choices.
According to a 2020 report. RV companies reported growth for eight straight years. increasing by 200 percent during that time, One of the biggest reasons for that growth is the fans of RVs, especially younger people. Plus, RV parks with lots of conveniences（便利设施）including free Wi-Fi, free breakfast, swimming pools are popping up everywhere.
Perhaps one of the greatest rewards for becoming an RVer is the RV community itself. Campers are usually friendly people with welcoming attitudes and a common love of the outdoors. In an RV park, as you share stories around the fire at night, it's easy to make lasting friendship.
Another great reason to try RVing is the fact that it's about 60 percent cheaper than a traditional vacation. You'll appreciate（感激）all those savings on your next road trip while knowing that your home is wherever you park it.
How do you deal with plastic bags from the supermarket? Throw them away or recycle them? How about eating them?
Some of the bags are not harmful to the environment. Humans and animals can safely eat them. Indian company EnviGreen has made a bag with natural materials. It looks and feels just like plastic, but can break down (降解) easily.
Ashwath Hedge who set up the EnviGreen company spent four years doing experiments with 12 natural materials. They include potatoes, corn, vegetable oil and bananas. He made the materials into liquid (液体) and used the liquid to make the bag.
Although the EnviGreen bag is more expensive than a common plastic bag, it has many advantages. According to the Wall Street Journal it takes 1,00 years for common plastic bags to break down. But an EnviGreen bag can naturally break down in less than 180 days. It also breaks down in less than a day in water, and in less than a minute in boiling water. Hedge was happy to show it in his interview with The Better India. In the interview, he put an EnviGreen bag in water and ate it with a smile.
There are more than 15,000 tons of plastic waste every day. But only 9,000 tons are processed. In China, 3 billion plastic bags are used every day. Maybe the EnviGreen bag could be a solution to the world problem of plastic pollution.
A study found that 52 of the most common species (物种) of birds in the USA have become smaller in size in the past 38 years. Scientists say species shrink (缩小) in size because of climate change.
This shrinking in size follows a rule called Bergmann's Rule. The rule says that animals in cooler areas are usually larger than those in warmer areas, which is because larger animals are able to keep warmer.
As global warming influences the planet, animals now have to make changes to face rising temperatures. Some of them shrink in size. Scientists studied over 70, 000 species of birds. They discovered that some birds in North America were shrinking in size. Studies on deer, insects and fish also show the same fact.
What does this mean for these species? First, global warming is happening faster than ever before. So, animals may not be able to change fast enough. Besides, when a species shrinks, other things will get influenced. When an animal's body shrinks, it may not be able to give birth to as many young as before-this may influence the size of the species population.
It is possible that scientists haven't yet completely understood how changes in size may influence the ability of animals to live. This shows the bigger problem with climate change-we aren't always able to predict what will happen when the Earth's temperature keeps rising. And that is the real danger.
A black cat crosses your path? That's bad luck. Walk under a ladder (梯子)? That's bad luck, too. Break a mirror-seven years of bad luck! Kill a bee? You got it…bad luck!
But not everything brings bad luck. Some things bring good luck, too. For example, if you carry a rabbit's foot with you at all times that will bring you good luck. Of course, nowadays, lucky rabbit's feet aren't made of real rabbit's feet. An acorn (橡子) in your pocket is good luck, too. If you make a wish when you see a shooting star cross the sky, the wish will come true.
If you throw rice on a just-married couple, they will have many children. If you catch a falling leaf on the first day of autumn, you will have good luck all year. If you blow out all the candles on your birthday cake in one blow, you will get whatever you want.
Are any of these things true? You may have blown out all the candles on your birthday cake in one blow last year, but did you get everything you wanted? Probably not. If you walk under a ladder and a bucket of paint falls on your head-that's pretty bad luck. But if some candy or fruit falls, that's good luck.
In fact, good luck and bad luck are only "superstitions (迷信). Millions of people all over the world believe in superstitions, especially good luck ones. But remember, no amount of acorns is going to save you if you make your decisions because of silly superstitions.
Earlier this year, China's education system announced a new "Double Reduction" policy (双减政策). "Double Reduction" refers to a reduction in the total amount and time of school homework and a reduction of after-school training programs.
"The policy really helps me." Shen Yuzhe, a 13-year-old boy from Beijing said. He is happy that he has less homework than before and he can finish it at school with no need to take it home. "I'm also happy to find there are fewer exams. Besides, teachers now teach at a much slower pace so that we have enough time to understand what we have learned. We don't need to buy workbooks any more and the exercises are mainly from the textbook." Shen Yuzhe said.
"The best thing about the ‘Double Reduction' is the increased time in after-school activities such as dancing, volleyball and drama." Zhang Hangming from Tianjin is also excited. He has joined a group called "leadership development", learning all kinds of useful skills. He likes it because teachers are also giving them more chances to learn from real life. For example, they went to research plants in a field during a science class. He believes that is a much better way to learn than just hitting the books.
Some people welcome the policy while others are still worried. Yu Zhiyue, a middle school student in Jiangsu still feel tired. "With the ‘Double Reduction', I have really got less homework to do. But my mother is worried that I will lose the chance to review what I've learnt in class without enough homework. So I have lots of after-school classes. Since I can only take these classes on weekdays now, weekdays have become especially long and tiring for me. From Monday to Friday, I need to take online classes at home after I come back from school." she said, "My parents told me the rules had changed but the competition had not gone away."
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C . 
D . 
Can you imagine a sea of sand three times bigger than India? This is the Sahara Desert, the largest desert in the world. It covers 11 countries in North Africa and is over 9 million square kilometers. That's more than 25% of Africa.
In the Sahara, temperatures are very different during the day and at night. It is much hotter during the day than at night. During the day, the hottest time is between 2 pm and 4 pm, when temperature rises to 33℃. But it is very cold at night—the coldest time is at 4 am, when temperatures fall to -1℃. The Sahara is very dry. The average precipitation (降水) in a year is only 70 millimeters.
How to stay alive in the Sahara Desert？Marco Rivera, our survival expert, has some tips.
Take warm clothes and a blanket. You will need a hat, long trousers and a woollen jumper to keep you warm at night. During the day, cover your body, head and face. Clothes protect you from the sun and keep water in your body. You will also need a warm blanket at night. It can get cold very quickly. When the temperature drops, it can be a shock and make you feel even colder.
A car is easier to see than a person walking in the desert. You can also use the mirrors from your car to signal to planes and other cars. You can use your car tyres to make a fire. A fire is easy to see. It will help people find you and it will keep you warm at night.
Try to drink some water at least once every hour. You need your water to last as long as possible. Drink only what you need. When you talk, you lose water from your body. Keep your mouth closed and do not talk.
If you eat, you will get thirsty and drink all of your water more quickly. You can eat a little, but only to stop you from feeling very hungry. Eat very small amounts of food and eat very slowly. You can live for three weeks with no food, but you can only live for three days without water.
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D . 
Xue Gailian, 65, has created many works with gourds (葫芦) using pyrography (烙画) in Shanxi Province over the past twenty years. She has also helped her villagers make money with the art form.
Twenty years ago, like most villagers of Wucun village in Shanxi's Wenshui county, Xue's family made a living by growing grapes. But they made only a little money because of the local weather and planting environment.
"One day, my husband brought back a good-looking gourd when he returned from outside the county," she said. "I liked it very much and wanted to keep it. So I made a painting on it."
Xue has been interested in painting since she was young. After learning and doing some researches, she started to plant gourds on her farm. After a good harvest (收获), she began to try pyrography. The art has been practiced since ancient times.
"At the beginning, I found it was not very easy for me to make good paintings," she said. "To improve my skills, I traveled to Shandong Province and Tianjin to learn from skilled artists."
Day by day, Xue's art became well-known in Chinese and foreign markets, including Japan and Singapore. She also set up a gourd pyrography society and has taught more than 100 local people for free.
"In the future, I will introduce more modern planting technology to improve the scientific planting of gourds," she said. "I will also further research and teach gourd pyrography skills to help villagers improve their lives."
She added: "I hope we can show more people the beauty of Chinese traditional arts and works through gourd pyrography."
a. Xue Gailian started to grow gourds on her farm.
b. Xue Gailian taught local people gourd pyrography for free.
c. Xue Gailian painted on a gourd that his husband brought back.
d. Xue Gailian found it difficult to learn gourd pyrography skills.
The next day would be Christmas, and Della had only＄1.87 to buy a gift for Jim. Now, there were only two possessions (财产). One was Jim's gold watch from his grandfather. The other was
Della's hair.
She went to the street with tears. Then she saw a sign, "Hair Goods." "Will you buy my hair?" asked Della.
"I buy hair," said the woman, "Take your hat off." "Twenty dollars," said the woman.
"Give it to me quickly," said Della.
The next two hours, she was searching through the stores for Jim's gift. She found a watch chain (表链) at last. As soon as she saw it she knew that it must be Jim's although it needed ＄21.
At about seven, Jim got home. "Jim, darling," she cried, "don't look at me that way. I had my hair cut off and sold. You don't know what a nice gift I've got for you. Let's be happy." "You've cut off your hair?" asked Jim.
"Cut it off and sold it," said Della. "Don't you like me just as well, anyhow?"
Jim took out a package and threw it upon the table.
"Don't make any mistake, Della," he said. "I don't think there's anything that could make me like my girl any less. But if you open that package, you may understand."
After opening it, she burst into joy but then she cried. For there lay the set of combs (梳子) that Della had always wanted. They were expensive, she knew. And now, they were hers, but her hair was gone.
But she hugged him and said, "My hair grows fast, Jim!"
Jim had not yet seen his beautiful gift. She held it out to him. "Isn't it wonderful, Jim? You'll look at the time a hundred times a day now. Give me your watch. I want to see how it looks on it."
But Jim put his hands under the back of his head and said, "Let's put our gifts away. I sold the watch to get the money to buy your combs."
From The Gift of the Magi
By O•Henry
a. Jim came back home at seven. b. Della decided to sell her hair.
c. Jim sent a set of combs to Della. d. Della bought a watch chain for Jim.
Stress (压力) has been a part of my life for as long as I can remember. When I was a kid, I stressed over some news reports. Why was there so many bad things happening in the world? And every age and stage comes with new problems: exams, friends, love, loss, job, family and death. One night, while I was facing a writing deadline, I could feel the worry setting in. Was it possible that stress was making me feel good?
As a psychologist (心理学家), Catherine Jackson, PhD, says, "In fact, stress is a must for people to live." Good stress is known as "eustress" and it comes with different advantages. Many studies have shown that "eustress" will help people to keep healthy and energetic.
Dr. Jackson finds stress can also increase your power and creativity to complete a task. "Another advantage is improved performance," she adds. Low levels of stress can make a good influence on brain power and improve memory and learning abilities in short time.
Dr. Jackson suggests reconsidering the word "stress" as "pressure." This could change how you go on to do with the situation. But it's important to tell the difference between them. "Stress nearly takes people's breath away, and the goal is to reduce it," Dr. Jackson explains, "but pressure is having something depend on your performance for a good result."
I changed the mind about stress that night. For the first time in my life, I was actually considering stress differently. In my case, my deadline finally had a good result. It's almost as if this pressure helped me get the job done. I might never be able to make bad stress disappear completely, but I can change my thoughts, and that's a step in the right direction.
B . 
C . 
D . 
