See a cellphone cover that you like on Taobao? Forget about placing an order, paying the bill online and waiting for days for it to be delivered to you. In the near future, you'll be able to get it in minutes just by hitting “print” on your computer.

    You might find it hard to believe that you could actually “print” an object like you would a picture. But it is not that hard to understand how it would work. Just as a traditional printer sprays ink onto paper line by line, modern 3D printers spread material onto a surface layer by layer, from the bottom to the top, gradually building up a shape.

    Instead of ink, the materials the 3D printer uses are mainly plastic, resin(树脂) and certain metals. The thinner each layer is—from a millimetre to less than the width of a hair—the smoother and finer the object will be.

    This may sound like a completely new technology, but the truth is that 3D printing has been around since the late 1980s. Back then, it was barely affordable for most people, so few knew about it.

    Last year, though, saw a big change in the 3D printing industry—printers became much cheaper. For example, 10 years ago a desktop 3D printer might have cost ￡20，000, while now they cost only about ￡1，000, according to the BBC.

    Taken out of the factory and introduced to more diverse and common uses, 3D printing can create just about anything you can think of—flutes , bikinis, jewelry, aircraft parts and even human organs. In fact, scientists from Cornell University in New York have just made an artificial ear using a 3D printer, according to Science Daily. The fake ear looks and acts exactly like a natural one.

    However, as 3D printing becomes more common, it may bring about certain problems—such as piracy. “Once you can download a coffee maker, or print out a new set of kitchen utensils (餐具) on your personal 3D printer, who will visit a retail  store again？” an expert in 3D printing told Forbes News. Even more frightening, what if anyone in the world could use a 3D printer to print out a fully functioning gun?

    A new generation addiction is quickly spreading all over the world. Weboholism, a twentieth century disease, affects people from different ages. They surf the net, use email and speak in chat rooms. They spend many hours on the computer, and it becomes a compulsive habit. They cannot stop, and it affects their lives.

    Ten years ago, no one thought that using computers could become compulsive behavior that could affect the social and physical life of computer users. This obsessional behavior has affected teenagers and college students. They are likely to log on computers and spend long hours at different websites.

    They become hooked on computers and gradually their social and school life is affected by this situation. They spend all free time surfing and don't concentrate on homework, so this addiction influences their grades and success at school. Because they can find everything on the websites, they hang out there. Moreover, this addiction to websites influences their social life.

    They spend more time in front of computers than with their friends. The relation with their friends changes. The virtual life becomes more important than their real life. They have a new language that they speak in the chat rooms and it causes cultural changes in society.

    Because of the change in their behavior, they begin to isolate themselves from the society and live with their virtual friends. They share their emotions and feelings with friends who they have never met in their life. Although they feel confident on the computer, they are not confident with real live friends they have known all their life. It is a problem for the future. This addictive behavior is beginning to affect all the world.

    The world seems gloomy (阴沉的) and gray when you're feeling blue. In fact, being down might even affect how you perceive (感知) the colour blue. A recent study about colour was published in the journal Psychological Science. It shows a direct connection between a person's ability to perceive colour and their emotions.

    Psychologists have long known that emotions can affect the way people perceive things. That's in part because chemicals from your brain might affect how you process what you see. “Color is such an important part of our experience,” says lead author Christopher Thorstenson, a psychologist at the university of Rochester, in New York. There's reason, he says, that sad people commonly describe the world as “colourless” and “gray”, and happy people use words like “bright” and “colorful”.

    In the experiment, the researchers randomly assigned people to one of two groups. People in the sadness group watched a sad scene from The Lion King. Those in the “amusement” group watched a comedy.

    Everyone was then asked to look at red, yellow, green, and blue patches (斑点) that had been changed to a grayish colour. “Some of the patches are pretty difficulty to make out,” Thorstenson admits he says it takes some time to figure out their shade. People were scored on how accurate their colour perception was. Then they completed an emotional evaluation.

    The result? Sad people had a hard time seeing the difference between shades along the blue-yellow colour axis (色轴). But they did not have problems seeing colours in the red-green spectrum (光谱). Thorstenson says this could be the result of an evolutionary need to see red as a response to anger.

    Thorstenson says these results highlight the possible important of dopamine in sight. Dopamine is a chemical that sends signals to the brain. Researchers are hoping to focus more on dopamine in the future. “We know dopamine affects how we see colours, too,” Thorstenson says “How we feel can really influence how we see the world around us” he says.

    It is quite natural for all of us to want to preserve and protect the foods we buy. We always think that the best way is by putting them in our refrigerators. However, there are certain foods which should never be placed in the fridge. The foods listed below may surprise you.

    Bananas in the fridge? Because they keep nutrients better outside the fridge, they should never be placed inside the refrigerator. Bananas are better kept on the counter until they ripen. The cold temperatures actually slow down the ripening process of the bananas, while the moisture and darkness of the fridge will only make them go bad.

    Potato should be placed in a cool, dry and dark space. By reason of the cold temperatures of the fridge, it can turn starch（淀粉）into sugar more rapidly. It is also recommended that potatoes be removed from plastic or paper bags they may have been placed in. Also, keep them unwashed, as well as in a well-ventilated cardboard box.

    Placing your onions inside your refrigerator will eventually end up turning them moldy and soft. Unpeeled（未剥皮的）onions should be kept out of plastic bags and fridge. One of the reasons for this is because unpeeled onions require and need air exposure for maximum life. If you have peeled an onion though, then you should keep it in the fridge, in a covered container.

    Believe it or not, placing garlic in your refrigerator will actually cause it to sprout（发芽）. The garlic will also got moldy and even rubbery. Moreover, inside your fridge, the look of the garlic will rarely change. This means you won't be able to tell if it's any good until you finally slice it open.

    My husband and I wanted desperately the instant transformation from typical consumers to eco-conscious people. We switched our light bulbs to CFL(compact fluorescent light) bulbs to conserve energy. We went about the house turning off lights and unplugging appliances that weren't in use. But the rate of global warming exceeded our snail's pace conversion to greenhood. So I pressed onward.

    I decided to put veganism(素食主义) at the top of our agenda. Vegans refuse any animal flesh or commercial goods made from any animal byproducts such as milk or fats. All the family applauded this option except for my husband. Some kind of animal needed to sacrifice its dear life for his meal or it was his dinner. I cooked up a storm, struggling to prepare nutritious meals dominated by not-so-obvious vegan dishes like bean burritos and high-fiber vegetable stir-fry. It took a few days before he realized that he hadn't been eating any meat.

    "I feel like eating beef." he announced. So that night, I took full advantage of a zucchini (一种南瓜), cut it into chunky(粗大的) pieces and cooked them. Then I covered them with spices. My beef-starved husband had some and a curious look crossed his face.

    "Where's the beef?"

    "Living peacefully somewhere on an open plain where it belongs."

    "I knew it" he murmured. "You've surely made great contributions to the boom in cattle." His taste buds were developed completely around the flavor of every kind of animal: cattle, pigs, deer, lamb, chickens and ducks. Converting him was like feeding grass to a lion.

    I'm all for preserving our planet, but what good would it do to save the earth for tomorrow's generation if today's died of starvation? The next day, we went out for burgers. I was very careful to place the paper bag into our recycling bin.

    Kincaid looked at his watch: eight-seventeen. The truck started on the second try, and he backed out, shifted gears, and moved slowly down the alley under hazy sun. Through the streets of Bellingham he went, heading south on Washington 11, running along the coast of Puget Sound for a few miles, then following the highway as it swung east a little before meeting U.S Route 20.

    Turning into the sun, he began the long, winding drive through the Cascades. He liked this country and felt unpressed stopping now and then to make notes about interesting possibilities for future expeditions or to shoot what he called "memory snapshots." The purpose of these causal photographs was to remind him of places he might want to visit again and approach more seriously. In later afternoon he turned north at Spokane, picking up U.S. Route 2, which would take him halfway across the northern United States to Duluth, Minnesota.

    He wished for the thousandth time in his life that he had a dog, a golden retriever, maybe, for travels like this and to keep him company at home. But he was frequently away; overseas much of the time and it would not be fair to the animal. Still, he thought about it anyway. In a few years he would be getting too old for the hard fieldwork. "I must get a dog then." He said to himself.

    Drives like this always put him into a sentimental mood. The dog was part of it. Robert Kincaid was alone as it's possible to be—an only child, parents both dead, distant relatives who had lost track of him and he of them, no close friends.

    He thought about Marian. She had left him nine years ago after five years of marriage. He was fifty-two now, that would make her just under forty. Marian had dreams of becoming a musician, a folksinger. She knew all of the Weavers' songs and sang them pretty well in the coffeehouse of Seattle. When he was home in the old days, he drove her to the shows and sat in the audience while she sang.

    His long absences—two or three months sometimes—were hard on the marriage. He knew that. She was aware of what he did when they decided to get married, and both of them had a vague sense that it could all be handled somehow. It couldn't when he came from photographing a story in Iceland and she was gone. The note read, "Robert, it didn't work out. I left you the Harmony guitar. Stay in touch."

    He didn't stay in touch. Neither did she. He signed the divorce papers when they arrived a year later and caught a plane for Australia the next day. She had asked for nothing except her freedom.