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 synapscs 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.

    Have you ever felt a sudden feeling of joy because you heard a favorite song playing? Then you know that music can have a strong effect on your emotions. {#blank#}1{#/blank#} It can help get you out of a bad mood (心情) or stay in a good one, says Alicia Ann Clair, professor at the University of Kansas. {#blank#}2{#/blank#}

    To cheer up, listen to Latin music or anything with a strong beat or a fast speed{#blank#}3{#/blank#}. When you want to relax after a busy day, music with a slower speed can calm you down.     

    Listen to calming music before you start any stressful activities, advises Dr. Clair. "Once you' re in a good state of mind, it' s easier to keep it." You can lower stress at work with music, too, by playing relaxing tunes (曲调). {#blank#}4{#/blank#} "If you listen to them all day long, you'll stop noticing them," Dr. Clair explains. Then the music won't have any effect.

    {#blank#}5{#/blank#}."To feel energetic, start with something relaxing, and then gradually increase the speed and beat," says Dr. Clair. For example, first play some nice slow love songs, and then listen to something more energetic. When you want to calm down after a busy week at work, just do the opposite.

    The nervous-looking young man had waited for a few moments—outside the jeweler's before he got enough courage to enter. He was warmly greeted by a young assistant. James felt a rush of blood to his face as he explained he would be bringing in his future wife to choose a birthday present. The assistant listened carefully and told him he'd better buy a necklace. He wasn't used to buying jewellery and was a little worried about over-spending. After some discussion as to a reasonable price and the type, the assistant showed him dozens of necklaces and helped him to choose. At last James chose one and left the shop promising to return at five o'clock. When, half an hour later than planned, James did return to the shop with his future wife, Laura, the assistant acted as if she had never seen him before. When she was asked to show them some necklaces, she first brought out some inexpensive ones for them to choose, and then gave them the one she had prepared. A choice was soon made and they went away satisfied. James would certainly come back to buy what he wanted.

    The bald eagle has been an official symbol (象征) of the United States for more than 200 years. Now it will share the stage with another American animal—the bison. Last spring, this huge, hairy animal became the country's national symbol.

    Bison, also known as buffalo, are the biggest land animals in North America. They have played a big role in American history.

    Long ago, millions of bison traveled across the U. S. Many lived in the grasslands of the Great Plains. For hundreds of years, American Indians in that area needed bison meat for food. They used the skins to make clothing and houses, and the bones to make tools.

    Later, many settlers moved to the Great Plains to set up farms and towns. They hunted bison in large numbers. By 1900, bison had almost died out. Only about 1,000 bison were left. Since then, people have worked hard to save the bison. Today, there are more than 400, 000 bison in the U. S. They live in protected areas and all over the nation. Their comeback is seen as a great success.

    To recognize the bison's importance in U. S. history, wildlife groups and American Indian groups asked U. S. lawmakers to make the animal a national symbol. Lawmakers passed a bill, or plan for a law, to do that. The President then signed the bill into law.

    U. S. Senator John Hoeven of North Dakota was one lawmaker who pushed to get the law passed. “The bison is an amazing animal,” he told Scholastic News. “It's a great symbol for a great country.”

    When was the last time you read a book or a magazine article? Do your everyday reading habits centre around updates on the Internet? In case you are one of countless individuals who don't make a habit of reading you may be passing up a great chance: Reading has a number of advantages and only a couple of advantages of reading are recorded below.

    Everything you read fills your head with new bits of information and you never know when it might be useful to you. The more knowledge you have, the better-equipped you are to overcome any challenge you'll ever face. Besides, here's a bit of food for thought：Should you ever find yourself in a terrible situation, remember that although you might lose everything else — your job, your possessions, your money, even your health — knowledge can never be taken from you.

    At the same time, the more you read, the more words you gain, and they'll surely make their way into your everyday vocabulary. Being able to express your ideas clearly in words is of great help and knowing that you can speak to higher-ranking people with self-confidence can be a great encouragement to your self-esteem（自尊）. Reading books is also important for learning new languages, as non-native speakers gain exposure to words used in context, which will improve their own speaking and writing fluency.

    When you read a book, you have to remember a lot of characters, their backgrounds, ambitions, history as well as the various plots(各种各样的情节) through every story. That's a fair bit to remember, but brains are wonderful things and can remember these things with ease. Amazingly enough, whenever you remember something new, new synapses(神经元的突触) are formed and existing ones are strengthened. How cool that is!

    No matter how much stress you have at work, in your personal relationships, or countless other issues faced in daily life, it all just slips away when you lose yourself in a great story. A well-written novel can transport you to other fields while an interesting article will distract(使分心） you and keep you in the present moment, letting stress away and allowing you to relax.

Who's Really Addicting You To Technology?

    “Nearly everyone I know is addicted in some measure to the Internet”, wrote Tony Schwartz in The New York Times. It's a common complaint these days. A steady stream of similar headlines accuses the Net and its offspring apps, social media sites and online games of addicting us to distraction.

    There's little doubt that nearly everyone who comes in contact with the Net has difficulty disconnecting. Then who's at fault for its overuse? To find solutions, it's important to understand what we're dealing with. There are four parties cooperating to keep you connected: the tech, your boss, your friends and you.

    The technologies themselves and their makers are the easiest suspects to blame for our distraction. Online services like Facebook, Google, twitter and the like rely on advertising revenue, so the more frequently you use them, the more money they make. No wonder these companies employ teams of people focused on improving their services to be as attractive as possible.

    Good as these services are, there are simple steps we can take to keep them from coming too close. However, less than 15 percent of smartphone users are willing to adjust their notification settings  meaning the remaining 85 percent of us default to (默认)the app makers' every preset devices.

    While companies like Facebook harvest attention to generate revenue from advertisers, other technologies have no such agenda. Take email, for example. We check email at all hours of the day we're obsessed, because that's what the boss wants. For almost all white-collar jobs, email is the primary tool of corporate communication. A slow response to a message could hurt not only your reputation but also your livelihood.

    Your friends are also responsible for the addiction. Think about this familiar scene. People gathered around a table, enjoying food and each others' company. Then, during an interval in the conversation, someone takes out their phone to check who knows what. Barely anyone notices and no one says a thing.

    The reality is taking one's phone out at the wrong time is more than an impolite behavior because, unlike other minor offense, checking tech is contagious (传染). Once one person looks at their phone, other people tend to do the same, starting a chain reaction.

    Hie technology, your boss, and your friends, all influence how often you find yourself using (or overusing) these gadgets. But there's still someone who deserves careful examination the person holding the phone.

    When people are doing something difficult they'd rather not do, the phone is used to transport them elsewhere. They can easily escape discomfort temporarily, by answering email or browsing the web under the excuse of so-called “research”. The truth is that we are working unproductively out of our bad habits.

    Personal technology is indeed more attractive than ever, which doesn't mean we shouldn't attempt to control our use of technology, instead, we should come to terms with the fact that it's more than the technology that's responsible for our habits. Our workplace culture, social norms and individual behaviors all play a part.