"Some secrets are hidden from health," wrote John Updike in his poem "Fever".

    I have experienced the truth of Updike's observation. My excellent health kept me from seeing some things—things that became secrets of sort.

    One relates to my son Chris. When I lost my health in March, I discovered something I had missed about him.

    Christopher has been a scholar and athlete through high school. He has behaved responsibly, engaged in community service. He has had an impressive peer group of serious students.

    While I saw these things, I had missed before what I experienced while in hospital. Early on, Christopher offered the clearest and most forceful words about my need to be positive and to fight acute leukemia(急性白血病). He never left the room after a visit without making me promise that I would be mentally tough and positive.

    During the first week, he showed his own mental toughness, researching leukemia and learning what the chances were. He even stopped my doctor outside the room, introduced himself and asked directly what he thought of my chances. He processed the answer without overreaction.

    Christopher did admonish(劝告) me against my choice of words the first week at home. I had moved back into my room from weighing myself, discovering a thin figure I did not know. I announced to him and my wife, “dead man walking”. I thought it was a way to lighten the obvious. He saw it as negativity and was strongly against such thinking and talking.

    When I resisted taking medicine sometimes, Christopher formed a “good-cop-bad-cop” team with his mother. Betsy gently and patiently encouraged. He directly and forcefully insisted. He always made the logical arguments for why I needed to take some awful pills.

    My health had hidden something from me; my ill-health helped me to see it.

    Most of us spend our lives seeking the natural world. We go fishing, sit in the garden, have a picnic, live in the suburbs or go to the seaside. The most popular leisure activity in Britain is going for a walk. When joggers jog, they don't run the streets. Every one of them tend to go to the park or the river.

    But despite this, our children are growing up nature­deprived(剥夺). I spent my boyhood climbing trees. These days, children are robbed of these ancient freedoms, due to problems like crime, traffic, the loss of the open spaces and strange new ideas about what is best for children, that is to say, things that can be bought, rather than things that can be found.

    The truth is to be found elsewhere. A study in the US: families had moved to better housing and the children were assessed for ADHD—attention deficit hyperactivity disorder(多动症). Those whose accommodation had more natural views showed an improvement of 19%; those who had the same improvement in material surroundings but no nice view improved just 4%.

    ADHD is one of the great problems of modern childhood. One study after another indicates that contact with nature gives huge benefits to ADHD children. However, we spend money on drugs rather than on green places.

    The life of old people is measurably better when they have access to nature. The increasing concern for the growing population of old people is in quality rather than quantity of years. And study after study finds that a garden is the single most important thing in finding that quality. Even problems with crime and aggressive behaviour are reduced when there is contact with the natural world.

    We need the wild world. It is essential to our well­being, our health and our happiness.

    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.

    Almost everyone wants to be happy, but not all know how to find happiness. Money and success alone do not bring lasting happiness. Aristotle, a Greek thinker, said, “Happiness depends upon ourselves.” In other words, we make our own happiness. Here are a few suggestions to help you be happier.

    The first secret of happiness is to enjoy the simple things in life. Too often, we spend so much time thinking about the future that we fail to enjoy the present, for example, getting into college or getting a good job. You should enjoy life's simple pleasures, such as reading a good book, listening to your favorite music, or spending time with close friends. People who have several close friends often live happier and healthier lives.

    Another secret to living a happy life is to be active, and have hobbies where you forget your problems and time. Many people experience dancing, or playing a sport, such as swimming. You can forget about your problems and only think about the activity.

    Finally, many people find happiness in helping others. Studies show that people feel good when they spend their time helping others. If you want to feel happier, do good things for someone. You can help a friend with his or her studies, go shopping to buy food for an elderly person, or simply help out around the house by washing the dishes.

    It is 6:00a.m.on the first day of the school year. In Chery brook Technology High School, mathematics teacher Eddie Woo is already at work.

    One of the first things before the first bell rings is to set up his tripod（三脚架）and iPad in the middle of the classroom. “I'm Mr. Woo. I record my lessons. I record all of them. In fact, I'm about to record this one,” he explains to his new maths class.

    He started posting videos online in 2012 for a student who was sick with cancer and missing a lot of school, so he started sharing them across the country and beyond. Wootube now has more than 38,000 subscribes(用户) and has attracted almost 4 million views worldwide.

    Cherybrook Technology High School principal(校长) Gary Johnson said Mr. Woo was helping maths teachers in Australia and making maths popular again. “He has an ability to simplify(简化) maths to a level where kids can really understand it.” Mr. Johnson said.

    12-year-old student Emily Shakespear said Mr. Woo's teaching style made maths easy and interesting. “I don't want to say it, but he sucked me into maths,” she said. Owen Potter, who attends high school in Cobar agreed. “It's difficult to understand how someone in Sydney can influence thousands of people across the whole country,” he said.

    Mr. Woo won the 2017 University of Sydney Young Alumni Award for Outstanding Achievement, and he was one of 12 Australian teachers honored at the Commonwealth Bank Teaching Awards.

    Along the river banks of the Amazon and the Orinoco there lives a bird that swims before it can fly, flies like a fat chicken, eats green leaves, has the stomach of a cow and has claw s ( 爪) on its wings when young. They build their homes about 4.6m above the river, an important feature for the safety of the young. It is called the hoatzin.

    In appearance, the birds of both sexes look very much alike with brown on the back and cream and red on the underside. The head is small, with a large set of feathers on the top, bright red eyes, and blue skin. Its nearest relatives are the common birds, cuckoos. Its most striking feature, though, is only found in the young.

    Baby hoatzins have a claw on the leading edge of each wing and another at the end of each wing tip. Using these four claws, together with the beak (喙), they can climb about in the bushes, looking very much like primitive (远古的) birds must have done. When the young hoatzins have learned to fly, they lose their claws.

    During the drier months between December and March hoatzins fly about the forest in groups of 20 to 30 birds, but in April, when the rainy season begins, they collect together in smaller living units of two to seven birds for producing purposes.