Sleep is something we all do. But some people need to sleep more than others. Babies sleep most of the time. Children in school sleep about ten to twelve hours a night. Most adults sleep only seven or eight hours. {#blank#}1{#/blank#}

    All parts of our bodies have to rest after they work.. Our arms need a rest after we lift heavy thing, When we run fast, our legs work hard. They get tired. We have to rest them. Our brains work hard, too. {#blank#}2{#/blank#}. We can sit quite still and rest our arms and legs. But our brains aren't resting. They go right on thinking as long as we are awake.

    Our brains slow down a bit when we sleep and dream. {#blank#}3{#/blank#} Instead of thinking wide-awake thoughts, our brains make up dreams. Some dreams are very pleasing. Some are not. Most of the time we forget them when we wake up.

    Scientists have tried to find out what would happen if people were not allowed to sleep. They asked some people not to go to bed. The people stayed up all night and all the next day. They stayed up the next night too, and the day after. They played games, but they made mistakes. They forgot things. {#blank#}4{#/blank#}

    The people grew rude and mean. They became angry with their friends. Finally they were too tired to stand up. When they sat down, they fell asleep.

    Scientists have found that if people are not allowed to sleep and to dream, they act in an unusual way. {#blank#}5{#/blank#} But we do know that we need it to stay well. So tonight have a good sleep. Lie down under the covers. Shut your eyes. Let your thoughts wander. Soon you'll stop thinking. You'll be asleep.

A. It was hard for their tired brains to work.

B. When we are awake, they help us pay attention to the world around us.

C. But babies, children, and adults — all of us need to have our sleep.

D. Good sleep helps to improve one's memory.

E. No one knows why sleep is so good for us.

F. But even as we sleep our brains are doing some work.

G. Of course you will have a good sleep.

    A student was one day taking a walk with his teacher. As they went along, they saw a pair of old shoes lying in the path. They were a poor farmer's, who was working in the nearby field.

    The student turned to the teacher, saying: “we will hide his shoes, and hide ourselves behind those trees, and wait to see what he will do.”

    “My young friend,” answered the teacher, “we should never make fun of the poor. Why not put a coin in each shoe, and then we will hide ourselves and watch?” The student did so and they both hid themselves behind the trees. The poor man soon finished his work, and came across the field to the path where he had left his coat and shoes.

    After putting on his coat, he put his foot into one of his shoes, and felt something hard. Then he bent(弯腰) down to feel what it was, and found the coin. Surprised, he looked at the coin, turned it around and looked at it again. He then looked around, but no person was seen. He put the money into his pocket, and continued to put on the other shoe. His surprise was doubled on finding the other coin.

    He couldn't control his feelings and fell to his knees, looked up to the sky and expressed his thanks. Then he spoke of his wife, sick and helpless, and his children without bread. He said the help would save them from dying.

    The student stood there deeply moved, and his eyes were filled with tears. “Now,” said the teacher, “Are you not much happier than if you had hidden the shoes?”

    It happens from time to time: you feel terrible when you take your first bite of a certain food, but after eating more, you find yourself enjoying it. This is what is called an acquired taste. But why do our tastes change?

    The answer, according to a recent study presented at an American Chemical Society meeting in Boston, lies in proteins in our saliva (唾液).

    Most of us tend to think saliva, almost entirely made up of water, is “only a mouth lubricant (润滑剂) helping us to swallow food,” the New York Times said. However, it also contains many proteins, which can help break food down, protect our teeth and help in tasting food.

    To explain how these proteins affect taste, a team of scientists from Purdue University in the US invited 64 volunteers to drink a bitter-tasting chocolate milk three times a day for six weeks and rated their tastes at the same time.

    According to the research, the participants found a strong bitterness on the first day, but the unpleasant flavor came to decrease as time went on and finally disappeared.

    That is not all that was changing. A noticeable increase in the levels of proline-rich (富含脯氨酸的) proteins was found in the saliva samples of the test subjects in the research period. These proteins serve to reduce the bitterness we taste and improve our adaptation to this flavor.

    “We think the body adapts to reduce the negative feeling of these bitter compounds,” said Cordelia Running, a food scientist at Purdue University. “Saliva changes flavor, which in turn changes eating choices.”

    This change in taste not only makes the food tastier, but also helps people keep an appetite for healthy food whose flavor might otherwise keep them away.

    One day, these proteins may even be extracted (提炼) and used as a separate food additive that could help people stick to healthy food whose flavor they continue to dislike, researchers told Science Alert. And according to Running, even it doesn't happen, the idea that “maybe some little piece of your body is actually trying to help you” could really benefit some people. Let's wait and see.

    I'm learning to drive in Switzerland. I think it will be a good idea to learn now because I have plenty of free time and am earning a little money to pay for lessons. I never learnt when I lived in the UK, so luckily driving on the "wrong" side isn't a problem.

    However, there are a lot of rules to remember. When you see a road to your right and there are no white lines on the ground, the cars to your right have the right to go before your car and you have to stop for them. In practice, lots of people forget this and cars either wait for each other while both drivers try to remember what to do, or beep (鸣喇叭) at each other if both try to go at the same time!

    When you drive round a roundabout, you should check all your mirrors. To remember how to do this, I often count them aloud—one, two, three—then a second glance at your blind spot when you're in the roundabout. One friend came driving with me and after about an hour asked why on earth I was counting. He had passed his test so long ago, he couldn't remember ever having to check three mirrors!

    Driving still seems scary to me so I drive quite slowly. I also don't know the countryside roads very well and don't know what's coming up round the comer or over the next hill. I drive slowly so I feel safe, but my driving instructor tells me to speed up or cars will bump into me from behind or try to overtake somewhere dangerous. So driving slowly is just as dangerous as driving fast!

    I'm not a very practical person so learning to drive has been a challenge. I don't have a lot of confidence and find it quite demotivating to do something that doesn't come naturally to me. To make driving more fun and interesting, I learn in Swiss German, so my instructor gives me instructions in Swiss. This way I've tricked myself into enjoying driving and hopefully will pass the test!

    As an old saying in China goes, "The days of the Sanjiu period are the coldest days." "Sanjiu period", which is in Minor Cold, refers to the third nine-day period (the 19th to the 27th day) after the day of the Winter Solstice (冬至). There are many different customs related to Minor Cold in China.

    Eating hotpot

    During Minor Cold people should eat some hot food to benefit the body and defend against the cold weather. Winter is the best time to have hotpot and braised mutton with soy sauce. But it is important to notice that too much spicy food may cause health problems.

    Eating huangyacai

    In Tianjin, there is a custom to have huangyacai, a kind of Chinese cabbage, during Minor Cold. There are large amounts of vitamins A and B in huangyacai. As huangyacai is fresh and tender, it is fit for frying, roasting and braising.

    Eating glutinous rice (糯米饭)

    According to tradition, the Cantonese eat glutinous rice in the morning during Minor Cold. Cantonese people add some fried preserved pork, sausages and peanuts and mix them into the rice.

    Eating vegetable rice

    In ancient times, people in Nanjing took Minor Cold quite seriously, but as time went by, the celebration of Minor Cold gradually disappeared. However, the custom of eating vegetable rice is still followed today. The rice is steamed and is unspeakably delicious. Among the ingredients (原料), aijiaohuang (a kind of green vegetable), sausages and salted duck are the specialties in Nanjing.

    One of the most expensive parts of flying is the cost of gas, not to mention the environmental effect it brings. An Israeli startup called Eviation Aircraft hopes to solve the problems. They displayed the world's first all-electric passenger airplane this week at the Paris Air Show.

    The lightweight plane­playfully called Alice­will be able to fly about 600 miles between charges. So it will focus on transportation between cities. It seats nine passengers and two crew members. A typical flight should cost a customer about $200.

    "The fact that we' re building an electric plane from scratch instead of just refitting an existing plane with a battery means that we can design our aircraft to be more effective and efficient than present planes," said Eviation co-founder Omer Bar Yohay. He predicts that per seat, per mile, the cost would be equal to that of a taxi or train.

    The demand for electrically powered aircraft is projected to reach hundreds of planes per year within the next decade. The change from gas to electric in power is expected to save millions of dollars in fuel costs, not to mention the environmental benefits including significant reduction of air pollution and noise levels.

    When it comes to the new possibilities, Yosef Abramowitz, an energy industry expert, said, "In modern life, it is important to fight climate change and now we have a path to do so in flying." Abramowitz, a tireless advocate for solar power, added, "The batteries will hopefully be charged with solar energy too."

    To help further save fuel costs, the designers have also invented a "taxibot" that drags planes from the passenger gate to the runway, so the planes needn't run their engines.

    After appearing at the Paris Air Show, the Alice will travel to the U.S. for further tests. It is expected that the first commercial flights will take off in 2022.

    "I think for the first time in a very, very long time, we can look at flight again and talk about the next revolution," Bar Yohay said.