After ruling the tennis world for almost five years,Roger Federer is adjusting to life at NO.2.But,like any king whose throne has been taken away,the Swiss star is already planning secretly bis return to power,beginning at this week's US Open.

    The problem is, many experts think he will never do it.They blame everything from age and tough competition to his racket and psychology.

    For years Federer, had enjoyed the view from the top.Competitors saw him as undefeated,and for the most part he was.However,before the 2008 season began,Federer had an illness that stole his strength and clearly affected his play on the court.Ever since,he has struggled to return to form,winning just two of his last 14 tournaments.

    "Twenty-seven is an age when your body starts talking back to you."tennis great John McEnroe told the New York Times.

    Pancho Sefura, another tennis great, noted that Federer is also facing a maturing crop of young talents."There are too many great players now,"he said,naming Britain's Andy  Murray,21,and Latvia's Ernests Gulbis,20.

    US magazine Sports Illustrated tennis columnist Jon Wertheim suggested that part of Federer's problem could be his insistence on using a small racket.He says that the smaller head demands ball control.But we see time and again that racket makers try to get players to use a certain stick-one they would like to market to consumers and it has a negative effect on the professional game.

    Sports psychologist Jim Loehr told the Times that Federer is probably feeling "a sense of doubt"after being considered as undefeated for so long.If Federer is to recover his state of being undefeated,Loehr said he must overcome his doubt."Federer doesn't need fame and money.But he has to get better.He has to go t.o a whole new level.That's the only way he stays in the game," he said.

    As for beginning his first Grand Slam in ages as the NO.2 seed, Federer said it might be for the best."Five years almost,I was expected to win every tournament I entered,"he said,"so maybe Rafael Nadal now feels what I had to feel for a very long time.It will be interesting to see how he handles it."

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    You may think, salt is just a simple cooking element we shake on our food for a little extra taste. But salt is much more than that. Without salt our muscles would not move. Our nervous systems would not operate. Our hearts would not beat.

    But do not think rubbing salt in a wound will help. Doing that would be painful and not heal the wound. To rub salt in a wound is an idiom that means to purposefully make a bad situation worse.

    Early humans got the salt they needed to stay alive from the animals they killed. But advances in agriculture led to a diet low in salt. So, humans needed to find other sources. Those who lived near the ocean or other natural sources for salt were lucky. Those who did not had to trade for salt. In fact, people used salt as a method of payment in many parts of the ancient world. The word “salary” comes from the word “salt”.

    Salt also played an important part in population movement and world exploration. Explorers understood that if they could keep food fresh, they could travel longer distances. So they used salt to preserve food and explored the world.

    Salt was so important that, according to food historians, it was traded pound-for- pound for gold. Today, people still use the expressions “to be worth one's salt” or “worth one's weight in salt”. The expressions describe a person of value.

    A person might also be called “salt of the earth”. That description means he or she is dependable and trustworthy. However, when you say “I think we should take what he said with a grain of salt” you mean you accept it but maintain a degree of doubt about its truth.

    It's been a hard time for rhinos (犀牛) lately. Recently the International Union for Conservation announced the western black rhinos had died out in the wild. It was last seen in western Africa in 2006. Now, those who work to protect the animals are trying to make sure that won't happen to other rhinos.

    19 south-central black rhinos in South Africa were driven to an area nearly 1,000 miles away, which was said to be the gentlest and quickest way to transport the animals. They were taken to a new home that would keep them safe from hunters.

    Though it is not allowed to hunt rhinos, many are still killed for their horns, which can sell for as much as $ 30,000 each. Most of them are used to make drugs as traditional medicines in Asian countries. Some people believe that the horns work well in treating pain, fever and even cancer. However, there is no medical evidence yet.

    Black rhino population began falling rapidly in the second half of the 1900s because of poaching. In fact, some people still hunt the animals at the risk of being put into prison. And many of the places where the animals used to live in were destroyed when people started building farms on the grasslands. Until the 1960s, about 65,000 black rhinos lived throughout most of Africa. Today, fewer than 5,000 are left—most of them in zoos and wildlife reserves.

    South Africa has the largest population of rhinos in the world. Poaching is an especially big problem in that country. So far, more than 340 rhinos have been killed there. Since 2003, the Black Rhino Expansion Project has been helping the south-central black rhinos in South Africa. The group works with landowners to find areas where rhinos can live safely away from hunters.

    So far, the group has successfully saved about 120 rhinos. Leaders of the project say the south-central black rhinos have seen a rise in numbers. It is hoped that, with continued support, these rhinos can escape the unfortunate result of the western black rhinos.

    International Children's Day is coming up on June 1st. Here we have chosen some films from around the world that are most worthy for children to see.

    E, T. the Extra-Terrestrial (1982)

    Director: Steven Spielberg

    Country: United States of America

    Storyline: A group of aliens are visiting the Earth at night. But one of the visitors from space is left behind and finds himself all alone on a very strange planet. Fortunately, he meets Elliot, a lonely boy himself, and slowly makes friends with Elliot's older brother Michael, his sister Gertie. Meanwhile government officers work day and night to track down the little alien. Elliot and others try their best to help the alien go home.

    Children of Heaven (1997)

    Director: Majid Majidi

    Country: Iran

    Storyline: Ali takes his little sister Zahra's shoes to the shoemaker to be repaired but loses them on the way home. There is no money to buy another pair. Ali makes a plan to share his shoes: Zahra will wear them in the morning and hand them to Ali at midday so he can attend school classes. Ali then enters a children's racing competition in hopes of receiving the third prize, a new pair of shoes.

    Kes (1969)

    Director: Ken Loach

    Country: United Kingdom

    Storyline: Bullied (欺凌) at school and getting little attention at home by his mother and older brother, Billy Casper, a 15-year-old boy from a working-class family, finds peace in his pet falcon (猎隼), Kes. With encouragement from his English teacher, Billy eventually discovers a positive purpose to his unfortunate life, until some bad thing comes.

    Experts say moods are feelings that tend to become fixed, influencing one's outlook for hours, days or even weeks. That's great if your mood is a pleasant one, but a problem if you are sad, anxious, angry or simply lonely.

    Perhaps the best way to deal with such moods is to talk them out; sometimes, though, there is no one to listen. Modern pharmacology（药理学）offers a lot of tranquilizers（镇静剂）. What many people don't realize, however, is that scientists have discovered the effectiveness of several non – drug methods to set you loose from an unwanted mood. These can be just as useful as drugs, and have the added benefit of being nonpoisonous. So next time you feel out of sorts, don't head for the drug – store but try the following methods.

    Of all the mood – altering self – help techniques, aerobic exercise（有氧运动）seems to be the most efficient cure for a bad mood. "If you could keep up the exercise you'd be in high spirits," says Kathryn Lance, author of Running for Health and Beauty.

    Researchers have explained biochemical and various other changes that make exercise compare favorable to drugs as a mood raiser. Physical work such as housework, however, does little. The key is aerobic exercise —running, cycling, walking, swimming or other repetitive and sustained activities that increase the heart rate, increase blood circulation and improve the body's use of oxygen. Do some of the activities for at least 20 minutes a session three to five times a week.

    The first organized system for sending messages began in Egypt around 1500 B.C. This system developed because the pharaohs frequently needed to send messages up and down the Nile River in order to keep their empire running smoothly. Later, the Persians developed a more efficient system for sending messages using men and horses. Messages carriers rode along the road system stretching from one end of the Persian Empire to the other. Along these roads, fresh men and horses waited at special stations to take and pass along any messages that needed to be sent. The stations where riders passed messages back and forth were built 23 kilometers apart, so the men and horses were able to travel quickly between them. The Romans later took up his idea and improved it by using a more advanced and extensive road system.

    In China, however, Kublai Khan had built up his own system for delivering messages. This system worked in the same basic way as the Roman system. The difference was that Kublai Khan kept 300,000 horses along the roads of this delivery lines. There were over 10,000 stations where a message would be passed from one rider to another with a fresh horse. In this way, Kublai Khan could receive messages from anywhere in the country in only a few days.

    It was not until the 1500s that a well-organized postal system appeared again in Europe. One family, the von Taxis family, gained the right to deliver mail for the Holy Roman Empire and parts of Spain. This family continued to carry mail, both government and private, throughout Europe for almost 300 years.

    In 1653, a Frenchman, Renouard de Velayer, established a system for delivering post in Paris. Postal charges at that time were paid by the recipient, but de Velayer's system was unique by allowing the sender to pre-pay the charges, in a similar way to the modern stamp. Unfortunately, de Velayer's system came to an end when jealous competitors put live mice in his letter boxes, ruining his business. Eventually, government-controlled postal systems took over from private postal businesses, and by the 1700s government ownership of most postal systems in Europe was an accepted fact of life.

    The thing that all these early systems had in common was that they were quite expensive for public use, and were intended for use by the government and the wealthy. However, in 1840, a British schoolteacher named Roland Hill suggested introducing postage stamps, and a postal rate based on weight. This resulted in lowering postal rates, encouraging more people to use the system to stay in touch with each other, His idea helped the British postal system begin to earn profits as early as 1850. Soon after that many other countries took up Mr. Hill's idea. And letter writing became accessible to anyone who could write. Today, the Roland Hill awards are given each year to "encourage and reward fresh ideas which help promote philately"(stamp collecting).