It's a popular belief that a fish's memory lasts for only seven seconds. It may seem sad to think that they don't remember what they've eaten or where they've been, and they don't recognize you or any of their friends — every moment in their life would be like seeing the world for the first time.

    But don't be so quick to feel sorry for them. A new study has found that fish have a much better memory than we used to think. In fact, certain species of fish can even remember events from as long as 12 days ago.

    In the study, researchers from MacEwan University in Canada trained a kind of fish called African cichlids to go to a certain area of their tank to get food. They then waited for 12 days before putting them back in the tank again.

    Researchers used computer software to monitor the fish's movements. They found that after such a long break the fish still went to the same place where they first got food. This suggested that they could remember their past experiences.

    In fact, scientists had been thinking for a long time that African cichlids might have a good memory. An earlier study showed that they behaved aggressively（挑衅地） in front of certain fish, perhaps because they remembered their past “fights”. But until the latest findings, there was no clear evidence.

    Just as a good memory can make our lives easier, it also plays an important part when a fish is trying to survive in the wild.

    “If fish are able to remember that a certain area contains safe food, they will be able to go back to that area without putting their lives at risks,” lead researcher Trevor Hamilton told Live Science.

    For a long time, fish were placed far below chimpanzees, dolphins and mice on the list of smart animals. But this study has given scientists a new understanding of their intelligence.

    LIANG TAO sold 80 pink Givenchy bags in 12 minutes. Becky Fang sold 100 Mini Cooper cars in just five. Both are wanghong, literally “red-hot on the web”. Every day millions of Chinese search social media for wanghong posts or tune in to live-streams for wanghong's opinions on everything. The fans are helping this new Chinese Internet star to make money out of their popularity—and to shake up the country's e-commerce industry in the process.

    A few of wanghong have been hired by luxury brands. Jaeger-LeCoultre, a Swiss watchmaker, hired Papi Jiang for a video ad targeting young urbanites (都市人), including her 27m fans on Sina Weibo, a Twitter-like microblog. Zhang Yi of iiMedia Research, a consulting firm, estimates that up to 15% of sales on shopping sites like Taobao or social-media apps such as WeChat are influenced by wanghong's public support. The length of a dress might be decided by a survey of a wanghong's fans; its launch date might be based on the number of hits, shares or comments it collects, some of which can cause last-minute design changes.

    This poses a new challenge for retailers(零售商), whose supply chains must respond ever more quickly to wanghong's opinions. Whereas previously a company would look for a celebrity to match its image, wanghong and their admirers are shaping goods.

    Another challenge comes directly from wanghong themselves. They increasingly make money not merely from online support or advice but by launching their own e-commerce stores. Sales of goods accounted for just under half of wanghong earnings of 53bn yuan ($8bn) in 2016, estimates Analysys, a Chinese market-research firm (the rest came mostly from live-show tips and adverts).

    Some wanghong are going a step further. In November Becky Fang launched her own clothing line. Part of her motivation, she says, was that the brands she supported did not always match the trends she was sharing with her followers. By creating her own brand, Becky's Fantasy, she have full control of the quality. She also gains a new income. For the time being only 3-5% of wanghong follow Becky Fang's example, iiMedia Research estimates. But it expects the model to become an industry in its own right, including entertainment and e-commerce, and driven by online data.

    Everyone wants to win, and everybody knows it. Take the case of Olympic athletes, who train hard each day for years to reach the top of their sport and hopefully win a gold medal. Since every competitor's goal is to win, we assume that the silver medalists would be less happy than gold-medal winners, but still happier than those in third place. Common sense says that our levels of happiness should have something to do with our levels of achievement – except that often this isn't the case.

    Researchers found that bronze medalists actually appeared on the whole to be happier than silver medalists. How could that be? The answer, in a word, is gratitude. Silver medallists, who compared themselves to the gold medalists, experienced disappointment at having been close to winning the gold, but falling short. The bronze medalists, on the other hand, were thankful to have won a medal at all, comparing themselves to all those who didn't even reach the Olympic platform.

    If happiness, then, is the aim of life, perhaps our achievement-centered culture is getting it all backwards. We focus on what we want rather than on what we have. We forget to be grateful, and as a result we forget to be happy.

    We're from a culture that teaches us to envy others – another person achievements – and that is always looking forward to what comes next. Yet in a better society, might we not look at what all of our earlier nexts have already earned us?

    I encourage any person who struggles with frustration （挫折）in their life to take out a notebook and a pen each evening before bed, and to write down all the things that they have gratitude for. It's not a cure for dissatisfaction, to be sure, but many people quickly discover that, when they actually stop to think about it, they have things pretty good and happiness comes.

    Those bronze medalists, after all, can't be wrong.

    Moksh Jawa, 16, a student at Washington High School in the US, has already become a legend(传奇) among students. “Why not?” might be his favorite question to ask.

    As a seventh-grader, he taught himself coding(编程) by studying on the Internet.

    As a high school freshman, he passed the AP Computer Science A exam with a 5, the highest score possible.

    As a sophomore (高中二年级学生), he developed his own online course and helped his classmates get through it because his high school didn't teach coding.

    Everything he did came from his own interest. His father sent him a link to Codeacademy, an online coding training program, in middle school. He learned a programming(编程) language all by himself after signing up to the website.

    “I just fell in love with computer science,”Jawa said. Along the way, he lit a fire of curiosity and passion among classmates to learn coding too.

    “All of my friends, especially the girls, were really, really afraid of computer science,” he said. But the subject and exam weren't things to be feared, he said, “Computer science is all about logic(逻辑), not about how smart you are. ”

    To make his knowledge available online, Jawa set about creating his own online course, with easy-to-follow lessons. He included quizzes and tests too.

    The course has so far attracted 3, 200 students across the US and in 120 countries and regions, including China, Ukraine and Algeria.  It shows, Jawa said, the huge need for coding lessons.

    When video lecturing, “I deliver it like I'm talking from one high school student to another,”Jawa said. “It's always great to make it as clear and fun as possible, and to try to keep my voice as energetic as possible. ”

    He also does that, when teaching members of the computer science club he founded at his high school.

    “His tutorials(辅导) were great, ”said Taj Shaik, the club's co-president, who took the whole course last year. “I'm definitely one of the early adopters(使用者) of Moksh. ”

    “He's pretty amazing, ”said Bob Moran, principal of Washington High School, who saw him lead the club. “He was just a fantastic teacher—clear, organized and entertaining. When a student got the right answer, he would throw him a candy. ”

    In the waters off Brisbane, Australia, a seven­foot­long sand tiger shark swims in pain. A two­foot­long spike sticks out of her side. It's a piece of fishing equipment that the shark ate carelessly. After traveling into her body, the spike punctured(刺) through the shark's stomach.

    A man swimming in the water notices the shark. Then, he warns Sea World Marine Park in the nearby town of Gold Coast. Sea World sends a 12­person team from its rescue center to where the shark was discovered in Moreton Bay Marine Park. Soon, they find her lying on the seafloor. "She'll die without help，"says Trevor Long, leader of the rescue center.

    Using an onboard crane(吊车), the rescuers move the shark into their boat's 13­foot­long tank(缸). Then Dr. David Blyde gives the shark pain medicine and performs an operation to remove the spike. After that, the team sails with the shark to Sea World 33 miles away. They place the fish in a 49­foot­long tank and wait to see if she gets better.

    To give the shark's stomach time to get better, she isn't fed for the first few days. A week after her operation, Long offers the shark a small, dead fish. The animal refuses to eat. But days later when he drops another fish into her tank, the shark enjoys her meal. By now the shark's wounds are getting better.

    Two weeks after her rescue, they take the shark back to the boat and return her to Moreton Bay Marine Park. As the fish is lowered by the crane to the water's surface, two rescuers jump into the ocean and guide her into the sea. From the boat, Long watches her swim away." The shark has another chance," Long says.

    I never saw my father home from work late or ill, nor did I ever see my father take a "night out with the boys". He had no hobbies but just took care of his family.

    For 22 years, since I left home for college, my father called me every Sunday at 9:00 am. He was always interested in my life—how my family was doing. The calls even came when he and my mother were in Australia, England or Florida.

    Nine years ago when I bought me first house, my father, 67 years old, spent eight hours a day for three days, painting my house. He would not allow me to pay someone to have it done. All he asked was a glass of iced tea, and that I hold a paintbrush for him and talk to him. But I was too busy, for I had a law practice to run, and I could not take the time to hold the paintbrush, or talk to my father.

    Five years ago, my 71-year-old father spent five hours putting together a swing set (秋千) for my daughter. Again, all he asked was that I get him a glass of iced tea, and talk to him. But again, I had laundry to do, and the house to clean.

    The morning on Sunday, January 16, 1995, my father telephoned me as usual, this time he had seemed to have forgotten some things we had discussed the week before. I had to get to church, and I cut the conversation short.

    The call came at 4:40 am. That day my father was sent to hospital in Florida. I got on a plane immediately, and I vowed (发誓) that when I arrived, I would make up for the lost time, and have a nice long talk with him and really get to know him.

    I arrived in Florida at 1:00 am, but my father had passed away at 9:12 pm. This time it was he who did not have time to talk, or time to wait for me.

    In the years since his death I have learnt much about my father, and even more about every single day.