What will power your house in the future？Nuclear, wind, or solar power？According toscientists at the Massachusetts Institute of Technology(MIT)in the US, it might beleaves—but artificial(人造的)ones.

    Natural leaves are able to change sunlight and water intoenergy. It is known as photosynthesis(光合作用). Nowresearchers have found a way to imitate this seemingly simple process.

    The artificial leaf developed by Daniel Nocera and hiscolleagues at MIT can be seen as a special silicon chip with catalysts(催化剂). Similar tonatural leaves, it can splitwater into hydrogen and oxygen when put into a bucket of water. The hydrogenand oxygen gases are then stored in a fuel cell, which usesthose two materials to produce electricity, located eitheron top of a house or beside the house.

Though the leaf is only about the shape of a poker card, scientistsclaimed that it is promising to be an inexpensive source of electricity indeveloping countries.“ One can imagine villages in India and Africa not longfrom now purchasing an affordable basic power system based on this technology, ”said Noceraat a conference of the American Chemical Society.

    The artificial leaf is not a new idea. The first artificial leafwas invented in 1997 but was too expensive and unstable for practical use. Thenew leaf, by contrast, is made ofcheap materials, easy to useand highly stable. In laboratory studies, Nocera showedthat an artificial leaf prototype(原型)could operatecontinuously for at least 45 hours without a drop in activity.

    The wonderful improvements come from Nocera's recent discoveryof several powerful, new andinexpensive catalysts. These catalysts make the energy transformation insidethe leaf more efficient with water and sunlight. Right now, the new leafis about 10 times more efficient at carrying out photosynthesis than a naturalone. Besides, the device canrun in whatever water is available；that is, it doesn'tneed pure water. This is important for some countries that don't have access topure water.

    With the goal to “make each home its own power station” and“give energy to the poor”, scientistsbelieve that the new technology could be widely used in developing countries, especially inIndia and rural China.

    Winters are long and unforgiving in North Dakota. The winter of 1996 was especially brutal. It was a hard time in my own life too, A neck injury had kept me flat in bed for nearly a year. “Just in time for Easter,” my husband, Dick, said. But how could I feel the joy when the snow was four feet deep and I had months of painful physical treatment ahead?

    I was doing the dishes one day, feeling hopeless when there was a tap against the glass. It was a branch of the troublesome cottonwood (棉白杨).Back in the fall of 1979, it was a new subdivision (分支) then, an eight-foot stick. The people who'd briefly occupied the house before us had placed the pipe from the pump next to it. The earth was so wet that the poor thing had fallen down, most of its bare root system pointing skyward, and blowing hopelessly back and forth in the cold wind. Dick decided to pull it out one day, but I disapproved of it.

    “Look at how hard it's trying!” I said, pointing to the way it strongly kept hold of the earth. “It deserves a chance.”

    Dick borrowed some tools. We packed dry soil around the tree and put up some stakes (桩) into the ground, making it stand upright. That winter was still terrible. Surprisingly, in the spring my “rescue stick” put forth a few leaves, then with lots of branches. The year after that, we were able to remove the stakes. By the 1990s that little stick was a giant, towering over the house.

    Now the tapping at the window continued, louder as the wind picked up, almost as though to tell me to look up. At last, I did. I caught ray breath. In the window against the icy blue sky, thousands and thousands of fresh red buds were waving in the wind.

    The tree was bursting with life and I had a wonderful Easter.

    If a diver surfaces too quickly, he may suffer the bends. Nitrogen(氮) dissolved(溶解) in his blood is suddenly liberated by the reduction of pressure. The consequence, if the bubbles (气泡)accumulate in a joint, is sharp pain and a bent body—thus the name. If the bubbles form in his lungs or his brain, the consequence can be death.

    Other air-breathing animals also suffer this decompression(减压) sickness if they surface too fast: whales, for example. And so, long ago, did ichthyosaurs. That these ancient sea animals got the bends can be seen from their bones. If bubbles of nitrogen form inside the bone they can cut off its blood supply. This kills the cells in the bone, and consequently weakens it, sometimes to the point of collapse. Fossil (化石)bones that have caved in on themselves are thus a sign that the animal once had the bends.

    Bruce Rothschild of the University of Kansas knew all this when he began a study of ichthyosaur bones to find out how widespread the problem was in the past. What he particularly wanted to investigate was how ichthyosaurs adapted to the problem of decompression over the 150 million years. To this end, he and his colleagues traveled the world's natural-history museums, looking at hundreds of ichthyosaurs from the Triassic period and from the later Jurassic and Cretaceous periods.

    When he started, he assumed that signs of the bends would be rarer in younger fossils, reflecting their gradual evolution of measures to deal with decompression. Instead, he was astonished to discover the opposite. More than 15% of Jurassic and Cretaceous ichthyosaurs had suffered the bends before they died, but not a single Triassic specimen(标本) showed evidence of that sort of injury.

    If ichthyosaurs did evolve an anti-decompression means, they clearly did so quickly—and, most strangely, they lost it afterwards. But that is not what Dr Rothschild thinks happened. He suspects it was evolution in other animals that caused the change.

    Whales that suffer the bends often do so because they have surfaced to escape a predator (捕食动物) such as a large shark. One of the features of Jurassic oceans was an abundance of large sharks and crocodiles, both of which were fond of ichthyosaur lunches. Triassic oceans, by contrast, were mercifully shark- and crocodile-free. In the Triassic, then, ichthyosaurs were top of the food chain. In the Jurassic and Cretaceous, they were prey(猎物) as well as predator—and often had to make a speedy exit as a result.

    When a terrible earthquake hit, many people were killed and many houses fell down. After the earthquake, all the newspapers reported many stories about some of the families who were in trouble.

    One Sunday, when I was reading a newspaper, a special picture touched me. It gave the clothing sizes of each family member. I thought that this would be a good chance to teach my children to help those who were less lucky than ourselves. I said to my seven-year-old twins, Brad and Brett, and three-year-old Meghan. "We have so much, and these poor people now have nothing. We'll share what we have with them."

    I filled a box with foods and clothes. While I was doing this, I encouraged the boys to choose their toys and donate some of their less favorite things. Meghan watched quietly as the boys took out their old toys and games and put them together. Then she walked away. A few minutes later she came back with Lucy, her much-loved doll. She put the doll on top of the other toys. "Oh, dear," I said. "You don't have to give Lucy. You love her so much." Meghan said, "Lucy makes me happy, Mommy. Maybe she'll make another little girl happy, too."

    I looked at Meghan for a long moment. She taught me a lesson. It's easy to give something that we don't want any more, but harder to give what we cherish (珍爱), isn't it?

    I spend half of my life with my mother and the other half with my father. My father lives with a twenty-pound cat named Tofu. He calls me his favorite daughter. I am an only child.

    My father's apartment is quite different from any other person's living space. Except for my room, there is no furniture. He doesn't like sofas or any comfortable chairs, so he has only a drawing table, a desk and his bed. He spends a lot of time lying on the studio floor. That's how he thinks, he says. Then he does yoga

    He has a big kitchen, and on top of the refrigerator is an old clock he winds every week for good luck. The last time the clock stopped, my father's car was towed(被警察拖走) and some other terrible things happened, so he has become very superstitious (迷信的) . When he goes out of town, he hires someone to feed Tofu and wind the clock so it won't stop.

    The one thing he has plenty of is house rules. You have to take off your shoes when you come in. He won't allow anyone who wears a baseball cap into his house. He says only baseball players should wear baseball caps and only the catchers should wear them backward. Every time I go to stay in his house, he makes up a new rule. "House rule number 579, no television programs with laugh tracks!" he will say. But then be can never remember the numbers, so they change constantly.

The rule that he always enforces is the one that requires me to write a two-page essay anytime I want something. He didn't speak English until he was sixteen, and he had a hard time learning to write it, so he wants me to become a good writer at an early age. This ritual(仪式)started when I asked him if I could have my ears pierced when I was nine. He said it was very cruel and told me I couldn't do it until I was thirty-five. But l kept asking him, and he finally said that if I wrote an essay and I could persuade him in writing why I wanted holes in my ears, maybe he would say okay. I wrote my first essay for my father, and after one month of writing and rewriting, he finally gave me his permission.

With such a strong artistic heritage, it's no surprise that England knocks it out of the park when it comes to world-class art galleries. These are the galleries you need to add to your must-visit list.

Royal Academy of Arts (RA), London

Not your standard gallery, the Royal Academy of Arts is led by artists to promote not just the appreciation of art, but its practice. It is world-famous for hosting some exhibitions that get everyone talking. Besides, what sets the RA apart is its engagement with the public through participatory experiences, allowing visitors to not only view art but become part of it in innovative ways.

Sainsbury Centre for Visual Arts, Norwich

Sitting on the edge of the University of East Anglia's campus, the Sainsbury Centre holds a collection of remarkable works of art spanning over 2,000 years. Inside the seminal Norman Foster building, you'll find artworks from around the world, including some stunning pieces of European modern art by Degas, Francis Bacon, and Alberto Giacometti.

Yorkshire Sculpture Park, West Yorkshire

Tearing up the rulebook when it comes to how we traditionally view art, the Yorkshire Sculpture Park strives to break down barriers by showing works from British and international artists in the open air. Set in hundreds of acres of West Yorkshire parkland, you'll see sculptures by some of the leading artists of the 20th century.

Whitworth, Manchester

After a sky-high £15 million development, the Whitworth is becoming one of the premier galleries in the north of England. Making full use of its picturesque park setting, the gallery has a beautiful art garden and a sculpture terrace (露台), all waiting to be explored. Inside the gallery, you can view an exciting programme of ever-changing exhibitions.