Food storing is common in members of the crow（乌鸦）family. A new study tested the birds outside this naturally occurring behaviour, which may have evolved（进化）specifically because it gives crows a survival advantage. Some crow species are known to naturally use tools to recover food. So the researchers tested whether the birds could store and recover a tool so they could get it at their food after a gap of 17 hours—something we wouldn't expect them to do naturally. But they were able to instantly select the tool out of a number of unnecessary items.

    In another experiment, the researchers taught crows to select a token （礼品券）from a number of items so that they could then exchange for food. Again, the birds then showed that they could plan for the future using this new behaviour. This is different from all of the previous studies in future planning, which have focused on naturally occurring behaviour. For example, we know that chimpanzees select, transport and save appropriate tools for future needs.

    These studies have shown that animals can plan for the future—but they left an important question open for debate. Are animals only able to plan to use abilities that have evolved to give them a specific advantage, or can they flexibly and intelligently apply planning behaviour across various actions? Most critics would say the former, as the animals were tested in naturally occurring behaviours.

    But the new research provides the first evidence that animal species can plan for the future using behaviour that doesn't typically occur in nature. This supports the view that at least some recognitive abilities in animals don't evolve just in response to specific problems. Instead, it suggests that animals can apply these behaviours flexibly across problems in a similar way to humans. We need to investigate how flexible behaviour evolved. Then we might be able to see how crows' ability to plan for the future fits in with their broader cognitive powers.

    The morning had been a disaster. My tooth was aching, and I'd been in an argument with a friend. Her words still hurt: “The trouble with you is that you won't put yourself in my place. Can't you see things from my point of view?” I shook my head stubbornly-and felt the ache in my tooth. I'd thought I could hold out till my dentist came back from holiday, but the pain was really unbearable. I started calling the dentists in the phone book, but no one could see me immediately. Finally, at about lunchtime, I got lucky.

    “If you come by right now,” the receptionist said, “the dentist will fit you in.”

    I took my purse and keys and rushed to my car. But suddenly I began to doubt about the dentist. What kind of dentist would be so eager to treat someone at such short notice? Why wasn't he as busy as the others?

    In the dentist's office, I sat down and looked around. I saw nothing but the bare walls and I became even more worried. The assistant noticed my nervousness and placed her warm hand over my ice-cold one.

    When I told her my fears, she laughed and said, “Don't worry. The dentist is very good.”

    “How long do I have to wait for him?” I asked impatiently.

    “Come on, he is coming. Just lie down and relax. And enjoy the artwork,” the assistant said.

    “The artwork?” I was puzzled.

    The chair went back. Suddenly I smiled. There was a beautiful picture, right where I could enjoy it: on the ceiling. How considerate the dentist was! At that moment, I began to understand what my friend meant by her words.

    What a relief!

    A unique experience awaits you at the Centre for Alternative Technology on the edge of the beautiful Snowdonia National Park.

    Over thirty years ago a group of people decided to try out alternative technologies. They chose a remote empty place, where rock used to be dug from the ground, as their base. Here experiments offering solutions to the world's energy problems were carried out, and nowadays many of these ideas have become common practice. You can experience all these for yourself in just one day with us, and then take away what you have learned and put it into practice at home. Be assured it will help you save on your household energy costs!

    Your visit to us begins with a ride up a steep 60-metre hillside on a railway which is worked by using the weight of water. At the top of the mountain you will enjoy beautiful views to the distant coastline. Then interactive displays show the power of wind, water and sun, while showing you what can be done in an ordinary household to reduce your influence on the planet.

    There was no soil when the project was started, so we created our organic gardens using our own home-made soil. You can enjoy woodland walks or even notice spring flowers growing on the roofs of environmentally-friendly buildings.

    In 2006 we opened our new eco-adventure playground for children, and we also run workshops where they can make models and become inventors of the future by putting wind, water or solar power into their own designs.

    The Centre for Alternative Technology is open all year round and has good rail, road and cycle links. In fact we offer a 50% reduction on the admission price if you arrive by bicycle. There is wheelchair access for disabled visitors—telephone us in advance if you would like assistance.

    Washington, D.C. Bicycle Tours

    Cherry Blossom Bike Tour in Washington, D.C.

    Duration: 3 hours

    This small group bike tour is a fantastic way to see a world-famous cherry trees with beautiful flowers of Washington, D.C. Your guide will provide a history lesson about the trees and the famous monuments where they blossom. Reserve your spot before availability—and the cherry blossoms—disappear!

    Washington Capital Monuments Bicycle Tour

    Duration: 3 hours (4 miles)

    Join a guided bike tour and view some of the most popular monuments in Washington, D.C. Explore the monuments and memorials on the National Mall as your guide shares unique facts and history at each stop. Guided tour includes bike, helmet, cookies and bottled water.

    Capital City Bike Tour In Washington, D.C.

    Duration: 3 hours

    Morning or afternoon, this bike tour is the perfect tour for D. C. newcomers and locals looking to experience Washington, D.C. in a healthy way with minimum effort. Knowledgeable guides will entertain you with the most interesting stories about Presidents, Congress, memorials, and parks. Comfortable bikes and a smooth tour route(路线) make cycling between the sites fun and relaxing.

    Washington Capital Sites at Night Bicycle Tour

    Duration: 3 hours(7miles)

    Join a small group bike tour for an evening of exploration in the heart of Washington, D.C. Get up close to the monuments and memorials as you bike the sites of Capitol Hill and the National Mall. Frequent stops are made for photo taking as your guide offers unique facts and history. Tour includes bike, helmet, and bottled water. All riders are equipped with reflective vests and safety lights.

    This may be music to your ears.

    Researchers P Jason Rentfrow and Samuel Gosling gave 3, 500 people a personality quiz. Then they asked them to name their favourite kind of music. "We found that the musical styles people like are closely linked to their personalities," Gosling says.

    RAP/HIP－HOP

    Known for their quick speech, some rappers can say more than 700 syllables (音节)a minute! If you like rap/hip－hop, you are energetic(精力充沛的)and have a way with words. You put a fresh spin on things, whether it's new moves on the dance floor or your hip style.

    CLASSICAL

    In the 18th century, classical musicians were like rock stars. Beethoven and Mozart, for example, played to packed concert halls.  If you like classical, you are open to new ideas and like debating with friends. Creative and imaginative, you can easily spend many hours scrapbooking, writing or painting.

    COUNTRY

    Country music came from the folk songs of English, Scottish, and Irish settlers of the southeastern United States. If you like country, you express your opinions well, which makes you the ideal class president or team captain. Traditional and loyal, you enjoy spending time with your family.

    POP

    Pop music is designed to appeal to(吸引)almost everyone, and it does. Each year, the industry brings in about 30 billion dollars! If you like pop, you are attractive to your friends. You can make big things happen, like planning for a huge party or inspiring your team to victory.

    ROCK/ALTERNATIVE

    In the 1950s, rock music created a brand－new culture. Teenagers, for the first time, had an identity(身份)separate from adults and children.

    If you like rock/alternative, you are a risk－taker who never accepts no for an answer. You rise to any challenge, like doing very well in a big exam or in the school play.

    If these personality profiles don't match you, that's OK. These are just for fun.

    We talk a lot in the U.S. about success. Success is the dream and the end point. And not by coincidence the idea that hard work leads to personal success is as American as apple pie.

    But the reality is that sometimes we fail. And sometimes things, through no fault of our own, don't go our way. We're faced with a life-changing diagnosis (诊断), the passing of a loved one or job loss. We don't, as a society, have as much to say here.

    I think uncertainty does us all harm. We'd feel better equipped to deal with uncertainty if we talked about it more. I had so fully bought into the belief that with enough effort, I could control what happened in my life. I actually caught myself thinking I could "work my way out" of my cancer. As it turns out, cancer doesn't really care about one's work.

    We might also make wiser decisions — this isn't just a feel-good exercise. For example, technology and medicine have progressed to the point that many patients are living longer than they would have even a decade ago. These are achievements worth celebrating. And yet I wonder if the focus on success is sometimes misguided here as well. If it is one reason why we tend to pursue expensive end-of-life treatments, they often accomplish little other than to make a patient's final days painful and frightening. The fact is that, when asked, many patients would rather focus on living meaningfully in their final days.

    My hope here is to make a case for thinking about meaning, in the same way we think about pursuing success. In that spirit, I've asked several people, each of whom has met misfortune, how they find meaning in their lives. The diversity in their responses reflects the fact that there are no right or wrong answers here. We each can find meaning in different things.