Honey from the African forest is not only a kind of natural sugar, it is also delicious. Most people, and many animals, like eating it. However, the only way for them to get that honey is to find a wild bees' nest and take the honey from it. Often, these nests are high up in trees, and it is difficult to find them. In parts of Africa, though, people and animals looking for honey have a strange and unexpected helper - a little bird called a honey guide.

    The honey guide does not actually like honey, but it does like the wax in the beehives (蜂房). The little bird cannot reach this wax（蜂蜡）, which is deep inside the bees' nest. So, when it finds a suitable nest, it looks for someone to help it. The honey guide gives a loud cry that attracts the attention of both passing animals and people. Once it has their attention, it flies through the forest, waiting from time to time for the curious animal or person as it leads them to the nest. When they finally arrive at the nest, the follower reaches in to get at the delicious honey as the bird patiently waits and watches. Some of the honey, and the wax, always falls to the ground, and this is when the honey guide takes its share.

    Scientists do not know why the honey guide likes eating the wax, but nothing can prevent the birds from making efforts to get it. The birds seem to be able to smell wax from a long distance away. They will quickly arrive whenever a beekeeper is taking honey from his beehives, and will even enter churches when beeswax candles are being lit.

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    We've all experienced the feeling that comes when your phone makes a sound to tell you that its battery level is low. It often comes at the worst times—when you're out on a trip and don't have a charger（充电器）, or when you're expecting an important phone call.

    Indeed, this feeling is so common that South Korean electronics manufacturer LG has given it a name: low battery anxiety（低电量焦虑）.

    According to a survey of 2,000 US adults conducted by the company last year, 90 percent of respondents said that they panic if their battery level reaches 20 percent or lower. And last month, UK telecommunications service provider found that around 15. 5 million Britons live in “constant fear” of their mobile phones running out of power, according to a survey by the company.

    “The problem is not about being unable to make calls, but is rooted in the fact that smartphones are now where we store digital memories,” noted the Daily Mail, However, battery worries don't just affect smartphone lovers. Many owners of electric vehicles also suffer from so-called “range anxiety”. This refers to the concern that the vehicle may not make it to its destination before the power runs out. Meanwhile, it isn't just low power that people worry about. A study carried out by South Korea's Sungkyunkwan University and China's City University of Hong Kong found that many of us also worry about not having constant access to our phone.

    This condition is known as homophobia, short for “ no mobile phone phobia（恐惧症）”. Symptoms include feeling uncomfortable when access to one's phone isn't possible, being unable to turn off your phone, and constantly topping up the battery to make sure it never dies.

    So, why do so many people treat their smartphone with such importance? The reason may be that they keep us connected to the people around us, and if we're unable to use our phone, we feel like we're cut off from our social life.

    With products with bigger batteries being released all the time-such as Xiaomi's Mi Max smartphone range or Tesla's Model S cars-battery anxiety may hopefully soon be a thing of the past.

    Many people have long dreamed of being able to fly around as simply as riding a bicycle. Yet the safety and strength of a flying bike was always a big problem. Over the past 10 years, developments in technology have moved the dream of personal flying vehicles closer to reality. Now, two groups of inventors say such vehicles may be available soon.

    The British company Malloy Aeronautics has developed a prototype (原型) of its flying bicycle. Grant Stapleton, marketing sales director of Malloy Aeronautics, says the Hoverbike is able to get in and out of small spaces very quickly." It can be moved across continents very quickly because it can be folded and packed," he adds.

    Mr. Stapleton says safety was the company's main concern. He says the designers solved the safety issue by using overlapping rotors to power the vehicle.

    The company is testing a full-size prototype of the Hoverbike, which will most likely be used first by the police and emergency rescue teams.

    In New Zealand, Martin Aircraft Company is also testing a full-size prototype of its personal flying device, called the Jetpack. It can fly for more than 30 minutes, up to 1, 000 meters high and reach a speed of 74 kilometers per hour.

    Peter Coker is the CEO of Martin Aircraft Company. He said the Jetpack "is built around safety from the start". In his words, "Reliability is the most important element of it. We have safety built into the actual structure itself, very similar to a Formula One racing car.

    The Jetpack uses a gasoline-powered engine that produces two powerful jet streams. Mr. Coker says it also has a parachute that would be used, if there should be an emergency. "It starts to work at very low altitude and actually saves both the aircraft and the pilot," he adds. Mr. Coker says the Jetpack will be ready for sale soon.

    Learning is so complex that there are many different psychological theories to explain how people learn. A psychologist named Albert Bandura suggested a social learning theory which shows that observation, imitation (模仿), and modeling play a primary role in this process.

    In Albert Bandura's opinion, people can learn through observation. Observational learning doesn't even necessarily require watching another person join in an activity. We can also learn by reading, hearing, or watching the actions of characters in books and films. However, just observing someone else's actions isn't always enough to lead to learning. Your own mental state also plays an important role in determining whether a behavior is learned or not. In addition, though in many cases, learning can be seen immediately when the new behavior is displayed, yet sometimes we can learn things even though that learning might not be immediately obvious, which means people can learn new information without showing new behaviors.

    Not all observed behaviors are effectively learned. Certain requirements need to be related to the observational learning process. For example, you need to be paying attention. Also your retention is an important part of observational learning as you need to pull up information later and act on it during the process. Once you've paid attention to the model and kept the information, it's time to actually perform the behavior you observed. Further practice of the learned behavior leads to improvement. Finally, you have to be motivated to imitate the behavior that has been modeled.

    Social learning theory have many real-world applications. For example, researchers employ it to look into and understand ways that positive role models can be used to encourage desirable behaviors. Besides, it's also applied in the field of education, and today, both teachers and parents recognize how important it is to model appropriate behaviors.

    Recently, as the British doctor Robert Winston took a train from London to Manchester, he found himself becoming steadily angry. A woman had picked up her phone and begun a loud conversation, which would last an unbelievable hour. Furious, Winston began to tweet about the woman. He took her picture and sent it to his more than 40,000 followers.

    When the train arrived at its destination, Winston rushed out. He'd had enough of the woman's rudeness. But the press were now waiting for her on the platform. And when they showed her Winston's messages, she used just one word to describe Winston's actions: rude.

    Winston's tale is something of a microcosm(缩影) of our age of increasing rudeness, fueled by social media. What can we do to fix this?

    Studies have shown that rudeness spreads quickly, almost like the common cold. Just witnessing rudeness makes it far more likely that we, in turn, will be rude later on. The only way to avoid it is to deal with it face to face. We must say, "Just stop." For Winston, that would have meant approaching the woman, telling her that her conversation was frustrating other passengers and politely asking her to speak more quietly or make the call at another time.

    The rage and injustice we feel at the rude behavior of a stranger can drive us to do odd things. In my own research, surveying 2,000 adults, I discovered that the acts of revenge people had taken ranged from the ridiculous to the disturbing. Winston did shine a spotlight on the woman's behavior — but from afar, in a way that shamed her.

    We must instead combat rudeness head on. When we see it occur in a store, we must step up and say something. If it happens to a colleague, we must point it out. We must defend strangers in the same way we'd defend our best friends. But we can do it with grace, by handling it without a trace of aggression and without being rude ourselves. Because once rude people can see their actions through the eyes of others, they are far more likely to end that strain themselves. As this tide of rudeness rises, civilization needs civility.

Iman, the last Sumatran rhino(犀牛) in Malaysia, died in 2019 — bringing the endangered species one step closer to extinction. Now, Malaysian scientists are hoping to use tissues and cells from Iman and other dead rhinos to bring the population back.

"Before the three rhinos (the last survivors in Malaysia) died, we got their cells, and the cells are still alive — which is why I'm quite confident," Dr. Lokman said. "If we don't have any cells, or have just tissue that isn't living anymore, we wouldn't be able to do anything. But now we have a living thing that we can use. "

The cells came from the rhinos'hearts, lungs and brains. What is the most important is that the team collected stem cells (干细胞). One possible approach is to develop these stem cells into an egg (卵子) and sperm (精子), to create an embryo (胚胎) that will be placed into a surrogate mother (代孕母亲). She will likely be another rhino, either a Sumatran rhino from another country or another species. The other method is to take the egg of a surrogate animal, remove the nucleus (细胞核), and join it with a Sumatran rhino's body cell. This technique was famously used to clone Dolly the sheep in 1996. Dr. Lokman and his colleagues are trying both ways. The team is still in the early stages; next, they need to find a suitable surrogate female.

Sumatran rhinos are listed as critically endangered by the World Wildlife Fund. There are less than 80 alive in Indonesia and Thailand. The fall in the population was first caused by hunting. Later, the situation was worsened by the loss of habitats and human activity. Unfortunately, there are now only five remaining rhino species worldwide, and all are threatened. Some sub-species have already died out; the western black rhino was declared extinct in 2013. And it is a pity that the last male northern white rhino died in 2019.