We humans spend about one-third of our lives asleep. This may sound like a lot of time, but it is not wasted. Sleep not only helps us stay healthy but it also helps our brains remember. Our brains need good sleep to remember what we do and learn during the other two thirds of our lives when we are awake.

    Researchers at the University of Wisconsin-Madison have found that sleep helps improve brain performance by shrinking(收缩)synapses in the brain. A synapse is the area where cells pass messages to other cells.

    Scientist Chiara Cirelli is a leader at the school's Center for Sleep and Consciousness. She told the reporter that sleep is when the human brain mixes information it has learned while awake into its general collection of knowledge. Meanwhile, the brain forgets unimportant details. This forgetting is important. It makes space for new learning and new memories.

    Cirelli said that the Centers research began with this hypothesis(假设): We sleep so that our brain can repair and refresh itself. She said the idea seems simple and reasonable. However, testing and discovering how it works has been extremely difficult.

    Synapses are only about 20-40 nanometers(纳米)wide. The team began their study by measuring the size of the synapses to look for changes in these already tiny spaces between nerve cells. Cirelli says the process(过程) is difficult because"all the actual measurements of the synapses have to be done by hand." The team had to wait until improvements in laboratory technology made it possible to see these tiny changes. A University of Wisconsin press release called the research a"huge job." Many research specialists worked for four years to photograph, rebuild and study certain areas of a mouse brain. The report also said the scientists measured 6,920 synapses.

    Cirelli says they found that our synapses shrink as our brains clean themselves during sleep. We wake up refreshed and ready to fill those synapses with new information. The research findings are the result of years of hard work at the University of Wisconsin Madison. The researchers published their findings in the journal Science.

    Plan your dream vacation to one of these excellent destinations.

    St. Lucia

    Abundant rainforests and splendid mountains are all reasons to visit this Caribbean island. St. Lucia offers the perfect mix of relaxation and adventure. To take in the breathtaking scenery, plan to hike the Piton Mountains or dive in the waters of Anse Chastanet.

    Banff. Alberta

    This Canadian destination will bring out the explorer in anyone who visits. From hiking and whitewater rafting to skiing and snowboarding, Banff offers travelers an abundance of year-round outdoor activities. The Lake Louise Ski Resort is one of the largest in North America and the striking photo opportunities of the Canadian Rockies from Moraine Lake can't be underestimated (低估).

    Machu Picchu

    According to travelers, a visit to this Peruvian UNESCO World Heritage (遗产) site is a once-in-a-lifetime adventure. Located in the Andes Mountains, it is the most familiar icon (象征物) of Inca civilization. Spend a few days accustoming yourself to the altitude in the neighboring city of Cusco, where you can experience a mix of Incan and Spanish cultures.

    Great Barrier Reef

    It's easy to see why the Great Barrier Reef is one of the Seven Natural Wonders of the World – it stretches nearly 1,500 miles along the eastern coastline of Australia and features about 3,000 reefs, 900 islands and more than 1,500 species of fish. Travelers can see these amazing natural structures from the air or underwater. However, large amounts of coral bleaching (褪色) caused by rising ocean temperatures put this place's continued existence at risk, so plan your visit soon to see this awesome sight up close.

    Do you know of anyone who uses the truth to deceive(欺骗)?When someone tells you something that is true, but leaves out important information that should be included, he can give you a false picture.

    For example, someone might say,“I just won a hundred dollars on the lottery(彩票).It was great. I took that dollar ticket back to the store and turned it in for one hundred dollars!”

    This guy's a winner, right? Maybe, maybe not. We then discover that he bought $200 worth of tickets, and only one was a winner. He's really a big loser!

    He didn't say anything that was false, but he left out important information on purpose. That's called a half-truth. Half-truths are not technically lies, but they are just as dishonest.

    Some politicians often use this trick. Let's say that during Governor Smith's last term, her state lost one million jobs and gained three million jobs. Then she seeks another term. One of her opponents(对手) says,“During Governor Smith's term, the state lost one million jobs!”That's true. However, an honest statement would have been,“During Governor Smith's term ,the state had a net gain of two million jobs.”

    Advertisers will sometimes use half-truths. It's against the law to make false statements so they try to mislead you with the truth. An advertisement might say,“Nine out of ten doctors advised their patients to take Yucky Pills to cure toothache.”It fails to mention that they only asked ten doctors and nine of them work for the Yucky Company.

    This kind of deception happens too often. It's a sad fact of life: Lies are lies, and sometimes the truth can lie as well.

    Arthur Miller(1915-2005) is universally recognized as one of the greatest dramatists（剧作家） of the 20^th century. Miller's father had moved to the USA from Austria-Hungary, drawn like so many others by the “Great American Dream”. However, he experienced severe financial hardship when his family business was ruined in the Great Depression (大萧条时期) of the early 1930s.

    Miller's most famous play, Death of a Salesman, is a powerful attack on the American system, with its aggressive way of doing business and its insistence on money and social status as indicators (标志) of worth. In Willy Loman, the hero of the play, we see a man who has got into trouble with his system, Willy is “burnt out” and in the cruel world of business there is no room for sentiment (情绪): if he can't do the work, then he is no good to his employer, the Wagner Company, and he must go. Willy is painfully aware of this, and at a loss as to what to do with his lack of success. He refuses to face the fact that he has failed and kills himself in the end.

    When it was first staged in 1949, the play was greeted with enthusiastic reviews, and it won the Tony Award for Best Play, the New York Drama Critics' Circle Award, and the Pulitzer Prize for drama. It was the first play to win all the three of these major awards.

    Miller died of heart failure at his home in Roxbury, Connecticut, on the evening of February 10, 2005, the 56^th anniversary of the first performance of Death of a Salesman on Broadway.

    Foxes and farmers have never got on well. These small dog-like animals have long been accused (控告)of killing farm animals. They are officially considered as harmful and farmers try to keep their numbers down by shooting or poisoning them.

    Farmers can do call on the services of their local hunt to control the fox population. Hunting consists of hunting a fox across the countryside, with a group of specially trained dogs, followed by men and women riding horses. When the dogs eventually catch the fox, they kill it or a hunter shoots it.

    People who take part in hunting think of it as a sport; they wear a special uniform of red coats and white trousers, and follow strict codes of behavior. But owning a horse and hunting regularly is expensive, so most hunters are wealthy.

    It is estimated (估计) that up to 100,000 people watch or take part in fox hunting . But over the last couple of decades the number of people opposed to fox hunting, because they think it is cruel, has risen sharply. Noisy confrontations between hunters and saboteurs have become so common that they are almost as much a part of hunting as the hunting of foxes itself. But this year supporters of fox hunting face a much bigger threat to their sport. A Labour Party Member of the Parliament, Mike Foster, is trying to get Parliament to approve a new law which will make the hunting of wild animals with dogs illegal. If the law is passed, wild animals like foxes will be protected under the ban in Britain.

    Have you ever thought of quitting your job when you feel exhausted? Maybe most of you would say "yes". After a particularly busy period at work, I decided to get away from it all by going on a hike in the mountains in southern France.

    Before I left, I read an interesting story in a magazine. It read, "Once, while I was riding on a crowded bus, the man sitting next to me threw his cell phone out of the window when his phone rang. I was surprised. He looked at me, shrugged (耸耸肩) and looked away. I had no idea whether it was his or stolen or whether he even knew what a cell phone was or not, but he clearly wanted to be free of it, because it clearly troubled him."

    Billions of people across the world use cell phones. Though cell phones are a wonderful way for communication, they often do the exact opposite. Using cell phones can increase stress within families and friends.

    So when I recently returned home, I got rid of my cell phone. Now I go outside without taking my phone with me. I've noticed things in my neighborhood I never noticed before, such as gardens. I've met new people, started conversations with neighbors I didn't speak to before and talked with some of my friends face to face instead of chatting over the phone.

    Instead of keeping me off from the world, stopping using my cell phone has helped me get even closer to my family and friends.