Liverpool, my hometown, is a special city. It is so unique that in 2004 it became a World Heritage（遗产）Site.

    I recently returned to my home city and my first stop was at a museum on the River Mersey. Blanketed in mist（薄雾），Victorian architecture rose from the banks of the river, responded to the sounds of sea-birds, and appeared unbelievably charming. When I headed toward the centre, I found myself surrounded by buildings that mirror the best palaces of Europe. It is not hard to imagine why, on first seeing the city, most visitors would be overpowered by the beauty of the noble buildings, which are solid signs of Liverpool's history.

    As if to stress its cultural role, Liverpool has more museums and galleries than most cities in Britain. At Walker Art Gallery, I was told that it has the best collections of Victorian paintings in the world, and is the home of modern art in the north of England. However, culture is more than galleries. Liverpool offers many music events. As Britain's No. 1 music city, it has the biggest city music festival in Europe, and its musicians are famous all over the world. Liverpool is also well-known for its football and other sports events. Every year, the Mersey River Festival attracts thousands of visitors, making the city a place of wonder.

    As you would expect from such a city, there are restaurants serving food from around the world. When my trip was about to complete, I chose to rest my legs in Liverpool's famous Philharmonic pub（酒馆）. It is a monument to perfection, and a heritage attraction itself.

    Being a World Heritage Site, my home city is certainly a place of “outstanding universal value”. It is a treasure house with plenty of secrets for the world to explore.

    In choosing a friend, one should be very careful. A good friend can help you study. You can have fun together and make each other happy. Sometimes you will meet fair weather friends. They will be with you as long as you have money or luck, but when you are down, they will run away. How do I know when I have found a good friend? I look for certain qualities of character, especially understanding, honesty and reliability(信任)．

    Above all else, I look for understanding in a friend. A good friend tries to understand how another person is feeling. He is not quick to judge. Instead, he tries to learn from others. He puts himself in the other person's place, and he tries to think of ways to be helpful. He is also a good listener.

    At the same time, however, a good friend is honest. He does not look for faults in others. He notices their good points. In short, a friend will try to understand me and accept me.

    Another quality of a friend is reliability. I can always depend on a good friend. If he tells me he will meet me somewhere at a certain time, I can be sure that he will be there. If I need a favor, he will do his best to help me. If I am in trouble, he will not run away from me.

    There is a fourth quality that makes a friend special. A special friend is someone with whom we can have fun. We should enjoy our lives, and we would enjoy our friendship. That is why I especially like friends who are fun to be with. A good friend likes the same things I like. We share experience and learn from each other. A good friend has a good sense of humor too. He likes to laugh with me. That is how we share in the joy of being friends. And I know that he is looking for the same quality in me.

    When I meet someone who is reliable, honest, and understanding, I know I've found a friend!

    The smallest kids on Earth are much smaller than you or your baby brother or sister. They're even smaller than the hairs on your head. We call them “NanoPutians”(纳米小人). Also known as NanoKids, the NanoPutians aren't real people. They are actually tiny molecules (分子) made to look a little bit like people.

    James Tour invented the NanoPutians as a way to teach kids about nanoscience, which refers to the study of things that are smaller than about 100 or 200 nanometers. “The exact size is less important than the possible applications of working with such tiny things,” Tour says, “Nanoscience is the study and development of the small so that it will affect the large.”

One of the goals of the research is to control individual atoms. Carbon, hydrogen, oxygen, and other types of atoms are the building blocks of the universe. They make up planets, rocks, people, trees, CDs — all the stuff out there. “Most things that people build come together in a top-down way”, Tour says. If you want to make a table, for instance, you cut down a big tree, make wooden boards, and hammer them together. Nature, on the other hand, builds things from the bottom up. When atoms join together they make molecules. Each molecule has a certain shape, and a molecule's structure determines what it can do. Molecules can make them come together to make a cell — or a tree.

    Tour and his co-workers turned these molecular structures into cartoon figures and made an animated(动画的) science video about the little people, set it to music and started showing it to kids in school while talking about how exciting research on small things can be.

    “Learning about the NanoKids has opened up a world of possibility for real kids who ordinarily would rather not study biology, chemistry or physics.” Tour says. When you look closely enough, the really small can be really cool.

    You've heard the predictions from some of the brightest minds about AI's influence. Tesla and SpaceX chief Elon Musk worries that AI is far more dangerous than nuclear weapons. The late scientist Stephen Hawking warned AI could serve as the "worst event in the history of our civilization" unless humanity is prepared for its possible risks.

    But many experts, even those who are aware of such risks, have a more positive attitude, especially in health-care and possibly in education. That is one of the results from a new AI study released Monday by the Pew Research Center.

    Pew canvassed the opinions of 979 experts over the summer, a group that included famous technologists, developers, innovators and business and policy leaders. The interviewed experts, some of whom chose to remain anonymous, were asked to join in the discussion of a serious and important question: "By 2030, do you think it is most likely that advancing AI and related technology systems will improve human capacities and control them?"

    Nearly two-thirds experts predicted most of us will be mostly better off. But a third thought otherwise, and a majority of the experts expressed at least some concerns over the long-term impact of AI on the "essential elements(要素) of being human." Among those concerns were data abuse, loss of jobs and loss of control brought by autonomous weapons and cybercrime(网络犯罪). Above all, by taking data in and spitting answers out, those "black box" tools make decisions in digital systems. It is an erosion(侵蚀) in our ability to think for ourselves.

    When pups are between 2 and 3months old, their mothers will abandon them for any number of reasons. With no mother to watch out for them, infant (婴儿) mortality of pups under one year skyrockets (飞涨) to around 90%. So, only about 10% of motherless, homeless pups survive.

    Without mothers, how are these abandoned pups supposed to survive? For the study, researchers Clive Wynne at Arizona State, Nadine Chersini at Utecht University, and Nathan Hal at Texas Tech University brought in 51 college students and asked them to rate the attractiveness of headshots (头部特写) of puppies at different ages.

    The pups peaked at different ages, but they were all ranked likable between six to eight weeks, since newly abandoned pups are competing with each other for human heartstrings (怜悯), evolution says they should be most likable around 6 and 11 weeks. This is around the time they are weaned (断奶) and let go of by their mothers.

    There are a few characteristics that humans find particularly adorable across species: big, forward-facing eyes, floppy and unstable limbs (肢), and a soft, rounded body shape. We're also keen to scream when animals have large heads in comparison to their bodies, and this reaction goes back to evolution.

    Called kinderschema (婴儿萌), these qualities are also apparent in human babies and necessary for their survival. The characteristics activate the decision-making part of the brain to encourage you to protect and nurture the baby. At the same time, the brain's pleasure center releases dopamine (多巴胺). With these two reactions, your brain makes you want to protect the baby and rewards you for doing so. With your protection, the baby can survive.

    The pupils of Grangetown High have been busy getting to know their newest and tallest classmate — a 7-meter-tall giraffe outside their school.

    The giraffe is a huge sculpture (雕像). The school's headmaster noticed it in an artist's garden as he drove past one day, and thought it would be perfect for his school. “I knew everyone would love it," he said, "because our basketball team is known as the Grangetown Giraffes, and they wear giraffes on their shirts. So I asked them to write to the artist, asking how much it would cost to buy the giraffe. He was very kind and got it ready to deliver (递送) in six weeks — all for nothing! It was expected to arrive one Sunday morning, so that the pupils would see it when they got to school on Monday — at that time they had no idea that we were getting it."

    The artist, Tom Bennett was a university professor of chemistry before he retired in 2012 and only took up metalwork a couple of years ago. "I've always drawn pictures," he said. I can even remember doing it on my first day at school — I drew a horse. I wanted it to be the best horse picture ever, but I don't think I succeeded."Tom's first metalwork was a bicycle on which he and his wife could go cycling together, “It was the most uncomfortable bike ever created," he said, "so I gave up making bicycles and went into sculpture instead."

    Meanwhile the pupils at Grangetown High are very happy with their new classmate. "We're going to hold a competition to give it a proper name," said one girl. "Everyone likes the expression on its face, so perhaps that will give us some ideas."