Dolphins(海豚) live in a dark underwater world. It's often impossible to see each other or anything else around them, so sound plays an important role in their survival. To communicate with each other, dolphins produce all kinds of sounds.

    Only other dolphins understand what the sounds mean. Scientists haven't uncovered their secret communication, except for one kind of whistle. It might last less than a second, but this whistle is a big deal. Why? Because these whistles are actually names of dolphins - and every dolphin has one. Scientists call these sounds a “signature whistle.” When other dolphins hear the whistle, they know which dolphin is calling.

    Dolphins often hunt by themselves but still need to stay connected to the group. Since they can't always see each other, dolphins use their signature whistles to check in with other dolphins hundreds of yards away. “In coastal areas, dolphins exchange whistles even when they're a third of a mile apart,” says Greg Campbell, who studies animals. That means dolphins shout out to group members that might be nearly five football fields away.

    What's amazing is who names the baby dolphin. Not the mother. Not an auntie dolphin or another group member. Scientists believe the baby dolphin itself comes up with the signature whistle. Like human babies, a baby dolphin plays with sounds throughout its first year. While testing its sound skills, a baby dolphin is doing something amazing. It's creating or figuring out its signature whistle. How or why it chooses its signature whistle is not clear. Studies show that most of the time the signature whistle is nothing like its mother's or group members' whistles.

    When the baby dolphin is about a year old, its signature whistle is set. It repeats it often so the other dolphins learn to recognize it.

    Deciphering(破译) dolphin names is just the beginning of figuring out what dolphins communicate about. Do they chat about sharks? Discuss the tides? Maybe they even have a name for people. Someday scientists are to decipher the rest of dolphins' communication.

    Part of the fun of watching sports events is following an exciting rivalry (竞争关系).

    But where do all these rivalries come from?

    Some rivalries start because athletes spend a lot of time close to opponents (对手).

    Other rivalries get personal. Things that one rival says that are thought to be not respectful to the other can cause a rivalry, even if the words are misunderstood. And sometimes, rivalries grow just because the athletes don't like each other's personalities.

    Some sports may also be more likely than others to cause rivalries. “Some sports only meet a few times, so there is less chance for rivalries to build,” For example, in sports where athletes perform on their own, such as diving, rivalries might also take longer to appear than in sports in which athletes compete at the same time. But in tennis, players often face each other, and rivalries are more likely to happen.

    So do the rivalries do good or harm to the athletes?

    Some believe that rivalries can be a good thing because they encourage athletes to try harder to win. But rivalries can also become too personal, taking athletes' attention away from their sports.

    Keegan agreed that rivalries often do athletes more harm than good. “They can be a huge distraction (分散注意力的事) and lead to focusing on the opponent more than the game,” he said.

    “Top athletes often have physical and mental training that they follow in order to worry less and prepare to compete”, Gould further explained. An important part of that preparation is preventing from distractions, including rivalries.

    “The better athletes don't care too much about a rivalry – they try to treat every competition the same,” Gould told LiveScience.

    A recent study, while showing a generally positive attitude toward science, also suggests a widespread worry that it may be "running out of control". This idea is dangerous.

    Science can be a force for evil as well as for good. Its applications can be channeled either way, depending on our decisions. The decisions we make, personally or collectively, will determine the outcomes of science. But here is a real danger. Science is advancing so fast and is so strongly influenced by businesses that we are likely to believe whatever decisions we come to will make little difference. And, rather than fighting for the best possible policies, we may step back and do nothing.

    Some people go even further. They say that despite the moral and legal objections, whatever is scientifically possible will be done-somewhere, sometime. They believe that science will get out of control in the end. This belief is dangerous too, because it fuels a sense of hopelessness and discourages then from making efforts to build a safer world.

    In our interconnected world, the lack of agreement in and out of the world of science can lead to the failure to control the use of science. Without a common understanding, the challenges of "controlling" science in this century will be really tough. Take human cloning for example. Despite the general agreement among scientists on its possible huge impact on traditional moral values, some countries still go ahead with the research and development of its related techniques. The outcomes are hard to predict.

    Therefore, discussions on how science is applied should be extended far beyond scientific societies. Only through the untied efforts of people with hope, can we be fully safe against the misuse of science and can science best serve mankind in the future.

    Airports are dull places where bored passengers kill time eating rubbish food they don't want and buying stuff they'll never need. Right?

    Wrong! Many of today's terminals（航站楼）around the world offer great entertainment, dining and shopping. With so much to offer, you're almost attracted to miss your flight.

    ⒈Changi Airport, Singapore

    It's the only one in the world with its own butterfly garden, and each of the three terminals has its own indoor playground and video game area.

    If you have a long wait you could always watch the latest movies at the free cinema, go to sunflower gardens or take a dip in the rooftop swimming pool.

    ⒉Incheon Airport, Seoul, South Korea

    A five-minute free shuttle bus ride will take you to the SKY72 Golf Club, with three courses and a driving range.

    There are seven gardens inside the terminal, an ice rink, a spa and the Museum of Korean Culture. There is even a casino（赌场）.

    ⒊Dubai Airport, UAE

    It has its own health club with a Jacuzzi, gym and swimming pool, or you can wander in the Zen Garden. The weary can take a rest in a sound-proofed pod with a bed for a while.

    ⒋Hong Kong Airport

    Not only does it have its own IMAX cinema, the airport is home to Green Live AIR, a hi-tech space offering both nine and 18-hole golf simulations（模拟）.

    For kids, there's the Dream Come True Education Park, where they take part in role-playing jobs, or the Aviation Discovery Centre, with themed exhibits and graphics, and the Sky Deck runway viewing platform.

    ⒌Munich Airport, Germany

    Go to the outdoor Visitor's Park to check out the historic aircraft, watch the planes from the viewing hill or browse in the souvenir shop. For kids, there's Kinderland, a fun paradise with a big “adventure plane”, films, games, arts and crafts, and a waiting room for their tired parents to relax in.

    And, of course, since we're in Bavaria there's a beer garden!

    I felt excited, curious and nervous at the same time. I was excited because I would be skipping（跳级）two grades. I was curious because I didn't know how high school students were taught.

    However, I was most nervous at the idea that I would be doing high school homework. I had just walked into the class when the bell rang. This wasn't a good start. But the kid in front of me looked very friendly. Luckily, since it was the first day of school, my teacher talked for about half of the period and we just had the rest of the period to start the class. I didn't know what he was saying at first, but when I saw the problems on the paper, I knew what to do. The next day, the kid said hi and I said hi back. We got into a conversation. It seemed that whenever I was talking to my friend, everyone stopped staring at me. Then the class started. It was easy. But I was still uncomfortable because I couldn't look around without meeting others' eyes, so I just kept my eyes on the whiteboard and on my textbook. However, my friend didn't show up the next day, and the eighth graders just kept on staring at me. I didn't know why.

    The next day everything changed. My friend was back to school. I was praised for my homework. Everyone stared at me less. Some started to be a little friendlier towards me. I felt at home at last here. My teachers also seemed pretty nice.

    who doesn't love sitting beside a cosy（舒适的）fire on a cold winter's night ? Who doesn't love to watch flames (火苗) curling up a chimney ? Fire is one of man's greatest friends, but also one of his greatest enemies. Many big fires are caused by carelessness. A lighted cigarette thrown out of a car or train window or a broken bottle lying on dry grass can start a fire. Sometimes, though, a fire can start on its own. Wet hay (草) can begin burning by itself. This is how it happens: the hay starts to rot (腐烂) and begins to give off heat which is trapped inside it. Finally, it bursts into flames. That's why farmers cut and store (贮存) their hay when it's dry .

    Fires have destroyed whole cities. In the 17th century, a small fire which began in a baker's shop burnt down nearly every building in London. Moscow was set on fire during the war against Napoleon. This fire continued burning for seven days . And, of course, in 64 A. D. a fire burnt Rome. Even today, in spite of modern fire - fighting methods, fire causes millions of pounds' worthy of damage each year both in our cities and in the countryside. It has been wisely said that fire is a good servant but a bad master.