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.

    When I was a child, my grandmother Adele took me to museums, restaurants, dances. She showered me gifts from her travels around the world. But I can only remember a book she gave me—one book that, to this day, I have not read. She presented me with her own favorite childhood book: Hans Brinker. My grandmother was happy to share this book with me. She even decorated the title page with her proud writing.

    I tried to read it. I adored reading, and would dive into a new pile of books from the library all at once. But something about Hans Brinker just wouldn't let me in. The story was set in Holland, a long time ago. It felt dull and unfamiliar, even though I was a fan of classics of other times and places. I simply read the first pages over and over. I could not progress.

    Standing on a bookshelf in our living room, the book was like something I avoided. It scolded me for not being interested, for not trying hard enough, for disappointing my grandmother. The book started to fit in, almost forgotten, until Adele asked. Had I read it? Did I like it? Always determined, she wanted to know the answer. I would make some kind of excuse, but feel bad, and open it again, hoping for a new reaction. The book weighed on me.

    Years passed and finally Adele and I both accepted that I would never read Hans Brinker. Eventually I cleared the book from the shelf. The Hans Brinker experience led me to set a rule that I've lived by ever since: Do not ask about a book given as a gift and don't let anything become your barrier. What Adele originally wanted to do is to give book-giving special meaning, but she increased the possibility of the owner to be a disappointment.

    How are you and your family going to celebrate Earth Day? It's a great day to get outside and ride a bike, but there are other ways you could spend the day. Here are four books. You can learn more about the earth and the animals that make the world a special place to live in.

    The Busy Beaver, by Nicholas Oldland

    Beaver is very, very busy, and he doesn't always think carefully. As a result, he makes a mess of the forest and ends up in hospital. Finally, he realizes how careless he's been and decides to make things right when he returns to the forest.

    Lessons from Mother Earth, by Elaine Mcleod

    Five-year-old Tess is visiting her grandmother and, for the first time, she visits the garden. Along the way, Tess's grandmother tells her the rules of the garden, "You must always take good care of our garden. Never throw rubbish around. There is plenty for everyone to share if we don't destroy the soil." The story is beautifully told as a caring conversation between a child and her grandmother.

    Luz Sees the Light, by Claudia Davila

    When Luz's community(社区) experiences a series of black-outs(停电), she quickly comes to understand the need to save energy and find other ways of doing things. With the help of her friends and neighbors, she creates a community garden and park that everyone can use. The book attracts many young readers.

    The Lorax, by Dr Seuss

    A young boy learns of the role of the Lorax as protector(保护者) of the trees, and how his home became polluted. The book contains memorable forestry conservation (森林保护).

    While the start of a new school year is always exciting, this year was even more so for some elementary school students in Auckland, New Zealand. They became the world's first kids to be “taught” by a digital teacher, Will. Will is just an avatar(用户头像) that appears on the student's desktop, tablet, or smartphone screen, not a human-like robot walking around the classroom.

    Auckland energy company Vector and AI company Soul Machines worked together to develop Will, which has been modeled after the human brain and nervous system, allowing it to perform human-like behavior. The digital teacher is currently assigned to teach Vector's “Be sustainable with energy,” a free program for Auckland elementary schools.

    Just like the humans it replaced, Will is able to instantly react to the students' responses to the topic. Thanks to a webcam(网络摄像头) and microphone, the avatar not only responds to questions the kids may have, but also picks up non-verbal cues(非口头提示). For instance, if a student smiles at Will, he responds by smiling back. This two-way interaction not only helps capture the students' attention, but also allows the program's developers to monitor their engagement, and make changes if needed.

    Vector's Chief Digital Officer, Nikhil Ravishankar says, “What was fascinating to me was the reaction of the children to Will. The way they look at the world is so creative and different, and Will really captured their attention.”

    Will, in place since August 2018, has been a great success thus far. However, regardless of how popular it becomes, Will is unlikely to replace human educators any time soon. For one, the avatar's knowledge base is severely restricted. But more importantly, even the smartest digital avatars could never predict and react to all the unexpected situations that educators have to deal with on a daily basis. However, it could come in handy as a “personal tutor”, providing kids with one-on-one help on specific subjects or even topics.

    A couple in their 60s has travelled 12,000 miles across 16 countries from Britain to China - riding their bikes all the way. Grandparents Peter and Chris stepped on the long journey after deciding to "do something a bit different". They traversed (横穿) cities, deserts, mountains and everything in between across Europe, the Middle East and the East Asia.

    Peter, 66, said the moment they finally had a look at the famous Great Wall after a year and a half of cycling 30 miles a day was "really exciting". At the end of their journey, the special pair didn't fly home but instead choose to book a cabin (舱) inside a 400m-long ship.

    "You never know what the day is going to bring. All you know is that you are going to get on your bike and cycle. Every day is an adventure and every day is new. Overall, the experience is unbelievable," Peter said.

    At first Peter and Chris set out to cycle from Britain in January 2017 but were forced home. They had cycled all the way to Hungary when Peter slipped and broke his leg. After seven months of recovery, the couple set out again in Britain. They finally arrived in China in November 2018.

    Both Peter and Chris agreed that the best part of the entire trip was coming across the kindness of strangers along the way, many of whom invited the couple for food and drink. Chris, 64, said, "It was a wonderful experience, particularly wonderful because of the amazing people we met along the way."