Tang Dynasty poets sang for about three centuries in different tones. There were many famous poets living in the Tang period such as Li Bai, Du Fu, Bai Juyi and Li Shangyin. Poems of the Tang Dynasty edited in the Qing Dynasty is a collection of about 48,900 poems that were written by over 2,200 poets. But it didn't cover all the poems of the Tang Dynasty.

    During the Tang Dynasty, poems were recited when lovers walked under the moonlight. Poems were also recited when soldiers fought on the battlefield. People recited them in the open air or at temple fairs.

    In the Tang Dynasty scholars had to be poets. Their readers were not only people of high social position but also common people. Poets recited poems; women singers sang poems and other ranks of people, including old women and children, read Tang poems. This atmosphere affected foreigners who visited the country at that time. As a result, Tang poetry was introduced to some adjacent countries, like Japan and Vietnam.

    Tang poetry is a most brilliant page in the history of ancient Chinese literature. It's a miracle in the cultural history of mankind. The Tang Dynasty was a powerful empire with a vast territory. It inherited Chinese civilization that went back to ancient times, and was combined with the best of other cultures and adopted the benefits of other nations in the world. Tang poetry wasn't the only spiritual wealth created by the Tang Dynasty people. Philosophy and religion, handwriting and painting and music and dance all gained new peaks of development. Tang poetry, however, was the jewel in the crown and its greatest achievement.

    People born in winter are more likely to suffer mental health disorders, according to a recent study carried out by researchers at Vanderbilt University in Tennessee.

    Researchers raised baby mice from birth to weaning (断奶) in either “summer” light cycles of 16 hours of light and 8 hours of dark or “winter” cycles of 8 hours of light and 16 hours of dark. A third group experienced 12 hours of light and 12 hours of dark a day.

    Then half the winter mice stayed in a winter cycle, while half switched to a summer schedule. The summer mice were similarly split. The mice raised in equal periods of light and dark were split into three groups, one of which stayed on the 12­hour schedule, one of which joined the winter group, and one of which joined the summer group.

    After 28 days, it turns out the summer­born mice behaved the same whether they stayed on the summer cycle or switched to winter. But among the winter­born mice, those that stayed in winter kept their previous schedule, while those that switched to summer stayed active for an extra hour and a half, which indicates that mice born and weaned in a winter light cycle showed dramatic disruptions（破坏） in their biological clocks.

    The finding is the first of its kind in mammals, and it could explain why people born in winter are at higher risk for mental health disorders.

    “We know that the biological clock regulates(管理) mood in humans,” said study researcher McMahon. “If the mechanism (机制) similar to the one that we found in mice operates in humans, then it could not only have an effect on a number of behavioral disorders, but also have a more general effect on personality.”

    Imagine you're standing in line to buy a snack at a store. You step up to the counter and the cashier scans your food. Next, you have to pay. But instead of scanning a QR Code(二维码) with your smart phone, you just hold out your hand so the cashier can scan your fingerprint. Or, a camera scans your face, your eyes or even your ear.

    Now, this type of technology might not be far away. As technology companies move away from the traditional password, biometric (生物特征识别的) security, which includes fingerprint, face and voice ID, is becoming increasingly popular.

    In 2013, Apple introduced the iPhone 5s, one of the first smart phones with a fingerprint scanner. Since then, using one's fingerprint to unlock a phone and make mobile payments has become a commonplace, bringing convenience to our lives. And since 2016, Samsung has featured eye-scanning technology in its top smart phones, while Apple's new iphone X can even scan a user's face. But despite its popularity, experts warn that biometrics might not be as secure as we imagine." Biometrics is ideally good in practice, not so much," said John Michener, a biometrics expert.

    When introducing the new iPhone's face ID feature, Phil Schiller, Apple's senior vice-president, said. "The chance that a random person in the population could look at your iPhones X and unlock it with their face is about one in a million." But it's already been done. In a video posted on a community website Reddit, two brothers showed how they were each able to unlock the same iPhone X using their own face. And they aren't even twins.

    "We may expect too much from biometrics," Anil Jain, a computer science professor at Michigan State University, told CBS News. "No security systems are perfect."

    Earlier last year, Jain found a way to trick biometric security. Using a printed copy of a thumbprint, she was able to unlock a dead person's smart phone for the police, according to a tech website Splinter. "It's good to see biometrics being used more," Jain told CBS News, "because it adds another factor for security. But using multiple security measures is the best defense."

    If you want to convince the boss you deserve a pay rise or promotion, the solution could be simple — eat the same food as they do. Psychologists have discovered managers are much more likely to instantly trust us if we choose the same dishes as them.

    During experiments, discussions over wages and work conditions were much more successful if both sides chose to snack on the same treats. And shoppers were much more likely to buy a product advertised on TV by someone eating a similar food to them at the time.

    The reason is thought to be so-called similarity attraction theory — where people tend to like others who have similar tastes or habits to themselves. But this is believed to be one of the first studies highlighting the role of food in this relationship. Researchers at Chicago University in the US conducted a series of experiments to examine food's role in earning trust.

    In a test, participants were told to watch TV — where someone pretending to be a member of the public praised a certain product. The volunteers were given Kit Kat bars to nibble (咬), while the TV people ate either a Kit Kat or grapes as they talked.

    The results showed viewers were much more likely to express an interest in buying the product if the TV showed the other person eating a Kit Kat too.

    The researchers added, “Although similarity in food consumption is not a sign of whether two people will get along, we find consumers treat this as such. They feel more trusting of those who consume as they do. It means people can immediately begin to feel friendship and develop a bond, leading to smoother transactions (交易) from the start.”

    Harley Street psychologist Dr. Lucy Atcheson said it was already known that wearing similar clothes could instantly create trust. But this was the first report that food had the same effect. She said, “This is really interesting. It makes sense as people feel they have common ground and can trust the other person. That means negotiations are more likely to be successful.”

    It is obvious that all of our childhood memories are not accidental. When you are a child, every scent, every sound, every move, every toy, the first day of school, the first kiss, the first step… Everything together makes what is the personality of a man. All these are pieces of one whole entity.

    I was about 6 years old. My mom's best friend left to another town and asked my mom to stay at her place with me for two days in order to look after her two sons. One was a little older than I was, and the second boy appeared to be super grown-up, for he was already fourteen. I always enjoyed staying at their place.

    I remember the second day we were supposed to have the come-back party for my mom's friend at her place. I woke up. Mom went to work and reminded me to be nice and clean by the time she came back. I stayed with Tony, the older of the boys and suddenly somebody called him and though he was not permitted to leave me alone-he left. He said it would not be long. But it took him forever. I realized that I was alone. I could not come out of the house, so I opened the window. I was so desperate. So lonely. So betrayed. At that moment I pulled the curtain so strongly that I fell on the floor. And there I was standing-one little criminal-desperate to escape and knowing that I would be punished for destroying the curtain that was not even ours.

But then something changed. I stopped weeping. I looked around and realized that I was in a safe place, and that mom would come back and kiss me no matter what I had done.

    This was a moment of pure happiness, not the happiness of getting a new toy or a dog, or going to the party of your best friend. It was the moment of clarity for me-the first time in my life when I realized that I was happy to have my mom and that I was safe. My eyes saw the world in different shades that moment. And by the way-I was not punished for the curtain. I fell asleep on my mom's knees.

    In most situations, light helps us see. But when it comes to looking at the night sky, light is actually a kind of pollution. It prevents our view of some of life's most striking sights: stars, planets, and even galaxies (银河系).

    "When I was a little boy, I loved the night sky. I remember looking up and the sky was filled with stars. I became an astronomer because I was amazed by their beauty," says Robert Gent, "Now in most big cities kids can't see the stars like I did."

    Normally, about 2，500 individual (单个的) stars are visible to the human eyes without using any special equipment. But because of light pollution, you actually see just 200 to 300 and fewer than a dozen from some cities. Only one in three Americans can see our own galaxy with the naked eyes. Those people live far away from the lights of big cities, office buildings, and shopping malls.

    Fortunately, there's an inexpensive and useful way. If we shine lights down at the ground instead of up into the sky, and use lower brightness levels, we can save big amounts of energy and keep the beauty of the night skies. Many cities and towns have passed laws limiting lights at night, making sure enough shine for safety without creating much light pollution.

    Light pollution affects more than our view of the heavens and can harm wildlife. Migrating birds (候鸟) sometimes fly over cities and become confused by the brightness, flying in circles until they drop from exhaustion. Sea turtles need dark beaches for nesting and won't approach bright lights. Too much light at night may even affect human health. For all these reasons, researchers are working on ways to use lights only when and where they are truly needed. Everyone deserves to look up at the sky.