We all have dreams sometimes. Some are sweet but some are nightmares. Almost all researchers in sleep explain that nightmares are a reaction to negative experiences that happen during waking hours. However, some of them believe that nightmares do have some real benefits. One 2017 study, for example, found that frequent nightmare sufferers rated themselves as more empathetic（共鸣的）.They also displayed more of a tendency to unconsciously mirror other people through things like yawning. People who have constant nightmares also tend to think further outside the box on psychoanalysis tasks. Some other researchers have found support for the idea that nightmares might be linked to creativity.

    People seeking cure for nightmares were not necessarily more fearful or anxious, but rather had a general sensitivity to all emotional experience. Sensitivity is the driving force behind intense dreams. Heightened sensitivity to threats or fear during the day results in bad dreams and nightmares, whereas heightened passion or excitement may result in more intense positive dreams. And both these forms of dreams may feed back into waking life, perhaps increasing suffering after nightmares, or promoting social bonds and empathy after positive dreams.

    The effects go further still. This sensitivity overflows over into perceptions and thoughts: people who have a lot of nightmares experience a dreamlike quality to their waking thoughts. And this kind of thinking seems to give them a creative edge. For instance, studies show that such people tend to have greater creative talent and artistic expression. And people who often have nightmares also tend to have more positive dreams than the average person.

    The evidence points towards the idea that, rather than disturbing normal activity, people who are unfortunate in having a lot of nightmares also have a dreaming life that is at least as creative, positive and vivid as it can be distressing and terrifying. What's more, this imaginative richness is unlikely to be limited to sleep, but also is filled with waking thought and daydreams. Even after people wake up and shake off the nightmare, in other words, a mark of it stays behind, possessing them throughout the day.

    When it comes to gift-giving, not only must the gift giver attempt to infer the recipient's(接受者的) tastes, needs, desires, and reactions, the gift selection may also be affected by the information which it would appear to convey about the giver and the giver-recipient relationship. The ancient practice of gift-giving is still common and important in modern cultures. For instance, Lowes Turner. and Willis (1971) mention a series of British Gallup Polls from 1963-1967, in which it was found that over 90 percent of the adult population did some Christmas gift-giving each year.

Gift-giving has been treated from a variety of related theoretical aspects. A famous theoretical analysis of the gift-giving process is an essay by French anthropologist- sociologist Marcell Mauss(1923). Based on his examination of gift-giving, Mauss concluded that gift-giving is a self-perpetuating(不停的) system of reciprocity. More specifically, Mauss summarized three types of obligations (义务): the obligation to give; the obligation to receive; the obligation to repay.

    The obligation to give may be based on moral or religious necessities, with the need to recognize and keep a status hierarchy(等级制度) or the need to establish or keep peaceful relations. Receiving is seen as similarly obligatory. Mauss noted however that there is a certain tension created in receiving a gift since acceptance is an implied recognition of dependence on the giver. This tension may then be reduced by meeting the third obligation, the obligation to repay. Failure to repay or failure to repay adequately results in a loss of status and self-esteem. Adequate or overly adequate repayment, on the other hand, creates an obligation to repay on the part of the original giver, and the cycle is reinitiated.

    Schwartz (1967) noted that beyond the functions served by the general process of gift exchange, the characteristics of the gift itself also act as a powerful statement of the giver's perception(洞察力) of the recipient. He also suggested that acceptance of a particular gift constitutes an acknowledgment and acceptance of the identity that the gift is seen to imply. Among children this may lead to lasting changes in self-perceptions, but probably gifts have less influence on the self- concept of an adult.

    There can be little doubt that gift-giving is a common experience in human life and consumer behavior.

    Americans use many expressions with the word "dog". People in the United States love their dogs and treat them well. {#blank#}1{#/blank#} However, dogs without owners to care for them lead a different kind of life. The expression, to lead a dog's life, describes a person who has an unhappy existence.

    Some people say we live in a dog-eat-dog world. {#blank#}2{#/blank#} They say that to be successful, a person has to work like a dog. This means they have to work very, very hard. Such hard work can make people dog-tired. And, the situation would be even worse if they became sick as a dog.

    {#blank#}3{#/blank#} This means that every person enjoys a successful period during his or her life. To be successful, people often have to learn new skills. Yet, some people say that you can never teach an old dog new tricks. They believe that older people do not like to learn new things and will not change the way they do things.

    {#blank#}4{#/blank#} People who are unkind or uncaring can be described as meaner than a junkyard dog. Junkyard dogs live in places where people throw away things they do not want. Mean dogs are often used to guard this property. They bark or attack people who try to enter the property. However, sometimes a person who appears to be mean and threatening is really not so bad. We say his bark is worse than his bite.

    Dog expressions are also used to describe the weather. The dog days of summer are the hottest days of the year. A rainstorm may cool the weather. But we do not want it to rain too hard. {#blank#}5{#/blank#}

    Have you ever imagined what it would be like to see the world through an animal's eyes? For example, what a chimpanzee sees as it sits at the top of a tree, or a penguin's view as it dives into the sea to catch its dinner?

    These questions are answered in the nature documentary Animals with Cameras, produced by the BBC. The three-part series was first aired in the UK last month. To explore animal stories "told" by the animals themselves, the documentary's filmmakers worked with scientists to develop cameras that wild animals could wear.

    "Never before have we seen such high-quality footage (连续镜头)directly from the animal's point of view, " BBC Nature executive producer Fred Kaufman told PBS." This miniseries greatly expands our comprehension of animal behavior and this camera technology opens up new possibilities for discovering so much more."

    Indeed, the groundbreaking technology provides a new viewpoint of the animal kingdom. New cameras with enough battery life to shoot for hours at a time were designed to be comfortable enough for animals to wear, according to the documentary's camera designer Chris Watts.

    The technical challenges didn't stop there. Some animals were very curious about the equipment, with some even fighting each other for the chance to wear a camera. In the case of chimpanzees, "we had to create dummy (仿造的)cameras, so that every chimpanzee could get one", the miniseries' wildlife cameraman Gordon Buchanan told Live Science.

    For animals that were comfortable enough to be with human beings, the cameras could be fitted and removed by hand. But for others, the cameras came off automatically using a timed release and were collected afterward. This meant that the cameras needed to be as tough as possible.

    To avoid disturbing the animals, scientists who were good at dealing with wildlife came to help by putting the cameras on the animals." The last thing we want to do is cause them distress." the documentary's producer Dan Rees told the BBC. "To follow an animal in the first place, there had to be a clear benefit in terms of knowledge about it that might be useful to protecting a species in the future.

    Their efforts certainly paid off. " Footage that captures (捕捉)these rare and exciting glimpses of animals bidden habits is important to scientists, but documentaries like Animals with Cameras also resonate with (引起共鸣)audiences, connecting them with the beauty - and danger - of wildlife in their natural environments," Live Science noted.

    Garbage sorting has become a hot issue around China, especially after Shanghai began carrying out a regulation on July 1.

    Beijing, as a forerunner in environmental protection, has thus been expected to follow suit. The capital of the country has long been campaigning for sorting and recycling household waste, as part of its environmental drive for sustainable growth, local media reported.

    The current regulation gives garbage sorting responsibilities to government departments, property management groups and other organizations. It also gives rules for companies, outlining how they're responsible for waste collection, transportation and treatment. Only individuals are not subject to responsibilities.

    The long-awaited revision will soon change the situation, "Taking out the trash without sorting it properly will be illegal," said Sun Xinjun, director of the Beijing Commission of Urban Management. In Shanghai, violators are now fined up to 200 yuan ($30)for trash-sorting violations. The maximum fine in Beijing will not be less than that, he said.

    The Beijing city government first set out to promote garbage sorting in 2009. Authorities have since called on citizens to sort their household waste into four types-recyclable waste, kitchen trash, dangerous waste and others-and leave it in a corresponding dustbin or trash can. Blue-colored dustbins signify items within are recyclable, green represents kitchen trash, red corresponds to dangerous materials and grey to other waste.

    To promote the awareness of garbage sorting and expand the base of participants, authorities have employed workers to help residents on the spot. With intelligent devices, those who throw in recyclable waste at given sites will be rewarded with bonus points, which can be used to buy daily goods. At some communities, there are no color-coded dustbins. Instead, a scheduled garbage collection service is offered to help improve the environment. In other communities, workers offer a door-to-door service to collect recyclables or kitchen waste.

    Beijing Environmental Sanitation Engineering Group has been promoting new garbage sorting facilities such as recycling cabinets and smart kitchen waste trash cans since 2016, Xinhua News Agency reported. Nearly 26,000 metric tons of household waste is generated across Beijing on a daily basis and 29 terminal garbage disposal facilities are working at full capacity. Nearly 9.3 million tons of household waste was processed in the city last year.

    People in Japan tend to live longer and stay healthier in their later years, with an increasing number of old people living alone. Japan is on a fast track to "ultra-age" with people aged 65 or above accounting for 28 percent of its total population in 2019；it was 26.7 percent in 2017. On the other hand, the number of births in 2019 fell to its lowest (about 941,000) since records began in 1899.

    Demand for care services for elderly people has increased. A shrinking (缩小) working population means fewer able-bodied adults are available to look after the elderly. State-provided facilities for the elderly are not enough which causes elderly people to turn to private ones but they are expensive.

    The country will be short of 380,000 of health nurses by 2025. The government has to turn to advanced robots to meet the shortage. A study found that using robots encouraged one third of the people to become more active and independent. Yet there is no robot that can provide the emotional support to the elderly.

    Japan provides a case study for China, which is also faced with a fast aging population. 17.23 million babies were born in China in 2019, about 630,000 fewer than in 2018. People aged 60 accounted for 17.3 of China's population in 2019. With a shortage of elderly care facilities and unbalanced supply, China may find it hard to deal with the rapidly increasing number of senior citizens.

    To meet the challenge, the Chinese government should make policy changes, which Japan is unwilling or unable to do or even consider. China should pay attention to the signals its aging population is sending and take proper and timely action.