Ninety years ago a man named Howard Carter made a great find. But he didn't discover an unknown people group or a new plant. He found the resting place of a king.

    People had seen signs of King Tutankhamun's tomb (坟墓) but had never found it. Finally, Carter's team discovered a set of steps that led down to some underground rooms. There Carter found the king's body and many of his treasures.

    Carter recorded his first impression in his popular book, The Tomb of Tut-Ankh-Amen：

At first I could see nothing, the hot air coming from the room causing the candle light to flicker (闪烁), but later, as my eyes grew used to the light, details of the room within appeared slowly and clearly, strange animals and gold—everywhere the light of gold... I was struck speechless with amazement, and when Lord Carnarvon, unable to stand the silence any longer, asked anxiously,  “Can you see anything?” it was all I could do to get out the words, “Yes, wonderful things.”

    The discovery has made King Tutankhamun, Tut for short, one of the best-remembered kings of Egypt. Tut became king when he was only 9 years old and ruled ancient Egypt from 1332 to 1323 B.C. No one is sure why, but he died suddenly before he turned 20. Because he died so young, there wasn't time to prepare a great tomb for him. So he ended up with a smaller tomb. Its small size was actually the reason why it stayed hidden for so long. And, Tut's tomb was not like other Egyptian kings'—it was not as damaged by time or robbers as other tombs. King Tut's tomb remains the best-kept royal (皇室的) tomb ever discovered. The discovery of this little tomb has helped people learn a great deal about ancient Egypt.

    Every animal sleeps, but the reason for this has remained foggy. When lab rats are not allowed to sleep, they die within a month. {#blank#}1{#/blank#}

    One idea is that sleep helps us strengthen new memories. {#blank#}2{#/blank#} We know that, while awake, fresh memories are recorded by reinforcing (加强) connections between brain cells, but the memory processes that take place while we sleep have been unclear.

    Support is growing for a theory that sleep evolved so that connections between neurons(神经元) in the brain can be weakened overnight, making room for fresh memories to form the next day. {#blank#}3{#/blank#}

    Now we have the most direct evidence yet that he is right. {#blank#}4{#/blank#}The synapses in the mice taken at the end of a period of sleep were 18 per cent smaller than those taken before sleep, showing that the connections between neurons weaken while sleeping.

    If Tononi's theory is right, it would explain why, when we miss a night's, we find it harder the next day to concentrate and learn new information — our brains may have smaller room for new experiences.

    Their research also suggests how we may build lasting memories over time even though the synapses become thinner. The team discovered that some synapses seem to be protected and stayed the same size. {#blank#}5{#/blank#} "You keep what matters," Tononi says.

A. We should also try to sleep well the night before.

B. It's as if the brain is preserving its most important memories.

C. Similarly, when people go for a few days without sleeping, they get sick.

D. The processes take place to stop our brains becoming loaded with memories.

E. That's why students do better in tests if they get a chance to sleep after learning.

F. "Sleep is the price we pay for learning," says Giulio Tononi, who developed the idea.

G. Tononi's team measured the size of these connections, or synapses, in the brains of 12 mice.

    There is virtue in working standing up. It sounds like a fashion. But it does have a basis in science.

    That, by itself, may not be surprising. Health ministries ask people for decades to do more exercise. What is surprising is that long periods of inactivity are bad regardless of how much time you also spend on officially approved high-impact stuff like pounding treadmills(跑步机) in the gym. What you need instead, the latest research suggests, is constant low-level activity. This can be so low-level that you might not think of it as activity at all. Even just standing up counts, for it invokes muscles that sitting does not.

Researchers in this field trace the history of the idea that standing up is good for you back to 1953, when a study published in The Lancet found that bus conductors, who spent their days standing, had a risk of heart attack half that of bus drivers, who spent their shifts on their backsides. But as the health benefits of exercise and vigorous(强度大的) physical activity began to become clear in the 1970s, says David Dunstan, a researcher at the Baker IDI Heart & Diabetes Institute in Melbourne, Australia, interest in low-intensity activity — like walking and standing — became weaker.

    Over the past few years, however, interest has been excited again. A series of studies, none big enough to provide convincing evidence, but all pointing in the same direction, persuaded Emma Wilmot of the University of Leicester, in Britain, to carry out a meta-analysis. This is a technique that combines diverse studies in a statistically meaningful way. Dr Wilmot combined 18 of them, covering almost 800,000 people and concluded that those individuals who are the least active in their normal daily lives are twice as likely to develop diabetes(糖尿病) as those who are the most active. She also found that the immobile are twice as likely to die from a heart attack and two-and-a-half times as likely to suffer cardiovascular disease as the most mobile. Crucially, all this seemed to be independent of the amount of vigorous, gym-style exercise that volunteers did.

    My name is Kobus Vermeulen. On February 16, 2015, I was one of five South Africans among the 100 people selected by Mars One to begin training to live on the Red Planet. The Dutch not-for-profit's aim is simple: build a human colony (殖民地) on Mars. Since I have begun this journey, the one question that people ask me most is why I want to leave a good planet for wasteland. Here is why.

    I have been interested in Mars since I was a child, and I always thought that if I had the opportunity to leave the planet, I would take it. So the why begins with a child's dream.

    However, as I grew, so did the why. In my eyes, since the 1970s the public has stopped trying to learn more about space. We've put our dream aside. We're satisfied with getting our dose (一份) of the future from sci-fi movies and comic books. And so the first part of my motivation (动机) is to get people thinking about space travel and the colonization (殖民化) of other planets in real terms again instead of just as sci-fi visions of the future.

    If we want that future, the truth is that we have to build it, and anything worth doing comes with risks. Somebody has to take the risks, and I, along with thousands of other people, am willing to take them.

    But it goes deeper than that. If the task of Mars One is even partially (部分地) successful, it will encourage a new generation of scientists and engineers that will build us an even better future.

    Without a dream, there is no reason to build those things. The public that does not try to understand science and technology does not choose good leaders. Leaders who don't care for science and technology do not make budgets (预算) for it. Besides, without the money, the dream dies. Projects like Mars One are like a focusing lens (聚焦透镜) for dreams. It is an opportunity to change hearts and minds at the grassroots level.

    Universities and colleges in the United States are trying new programs for international students to increase enrollment and income. Some universities are experimenting with bringing international high school students to their campuses. These programs permit students to complete their high school diploma while earning college credit at the same time.

    One example of this model is at the University of Southern Maine, or USM. The program is called the "International Academy". The school is expecting its first class of international high school students this fall. Joanna Evans is the director for the academy. The program is officially a "boarding school on a university campus" that serves 11th and 12th grade international high school students only.

    The students will take classes at the University of Southern Maine to complete their high school diploma. However, because the classes are university-level, the students will receive college credit at the same time.

    According to Evans, the students they admit will have to be very strong. Their course schedule will be the same as taking only advanced-placement courses. The goal is that, by the time they complete their high school diploma at the academy, they will be ready to start college as a third-year college student.

    Their English language skills also must be strong. The Academy looks for students with a minimum Test of English as a Foreign Language, or TOEFL score of 79,or a 6.5 on the International English Testing System, or EELTS. However, there are classes available to provide additional English language training when the students arrive if they need it.

    All incoming students at the academy are required to take a college writing class in their first term. If English is not their first language, they will take a class taught by teachers with a background in teaching students who speak English as a foreign language.

    Although they are only high school students, the expectations are the same as college students. "Students need to be ready to take university classes, and that is the deal" Evans said.

    Last year, on report card day, my son and a bunch of his 13-year-old friends piled into the back seat of my car, ready for the last-day-of-school party at McDonald's. "Jack got a laptop for getting straight A's, and Laurie got a cell phone," one boy said. "Oh, yeah, and Sarah got an iPod Nano, and she's only in third grade," said another. "And how about Brian? He got $10 for each A."

    I suddenly became concerned. These payoffs might get parents through grammar school, but what about high school and beyond? What would be left after the electric guitar, the cell phone, and the portable laptop?

    I saw the road ahead: As the homework load increased, my income would decrease. I saw my comfortable lifestyle vanish before my eyes — no more of those $5 bags of already-peeled organic carrots. No more organic anything!

    I started to feel surprised and nervous. Would every goal attained by my two children fetch a reward? A high grade point average? A good class ranking? Would sports achievements be included in this reward system: soccer goals, touchdowns(橄榄球触地得分(, runs-batted-in(棒球打点得分(? What about orchestra(管弦乐团(? Would first chair pay more than second? I'd be penniless by eighth-grade graduation.

"We never paid anything for good grades," said my neighbor across the street, whose son was recently accepted at MIT. "He just did it on his own. Maybe once in a while we went out for pizza, but that's about it."

    Don't you just hate that? We're all running around looking for the latest electronic products, and she's spending a few dollars on pizza. She gets motivation; we get negotiation.