Mark felt that it was time for him to take part in his community, so he went to the neighborhood meeting after work. The area city council (委员会) woman was leading a discussion about how the quality of life was decreasing. The neighborhood faced many problems. Mark looked at the charts taped to the walls. There were charts for parking problems, crime, and for problems in vacant buildings. Mark read from the charts, “Police patrols(巡逻) cut back, illegal parking up 20%”. People were supposed to suggest solutions to the councilwoman. It was too much for Mark. "The problems are too big," he thought. He turned to the man next to him and said, "I think this is a waste of my time. Nothing I could do would make a difference here."

    As he neared the bus stop on his way home, Mark saw a woman carrying a grocery bag and a baby. As Mark got closer, her other child, a little boy, suddenly dashed into the street. The woman tried to reach for him, but as she moved, her bag shifted (滑落), and groceries started to fall out. Mark ran to take the boy's arm and led him back to his mother. Then he picked up the groceries while the woman smiled in relief. "Thanks!" she said. "You've got great timing!" "Just being neighborly," Mark said. As he rode home, he glanced at the walls of the bus. On one of them was “Small acts of kindness add up.”, Mark smiled and thought, "Maybe that's a good place to start."

    One of the most exciting and interesting international cities to visit is London, England. Here is a look at four free things to do during a vacation to London.

    Visit the Trafalgar Square

    Built more than 200 years ago, Trafalgar Square is a popular gathering place for locals and travelers, too. The area is close to good shopping and dining opportunities, and there are usually some sorts of public events or celebrations going on there during most weekends.

    Wander Along the Thames

    Visitors wanting to sec some great architecture, attractions and views should spend an afternoon walking along the River Thames. The best place to start is at the world-famous London Bridge crossing over the river and you can walk all the way to Westminster Bridge a short distance away. Travelers doing this will find themselves passing by a great many historic buildings.

    Explore the Local Markets

    While purchasing items at any of the open markets in London is not necessarily free, walking through them to view the merchants（商人）, their products and the other shoppers is of great fun. Some of the popular open markets in London worth visiting include Spitafields Market, Portobello Road Market and Leadenhall Market.

     Visit the British Museum

    One of the top museums in the entire United Kingdom can be found in London, and it charges no admission（人场费）for entry. This museum is so highly regarded that it is not only popular with locals and tourists, it is also seen as a major and valuable scholarly resource.

    As my dad unwrapped（打开）the new bicycle helmet（头盔）that I got him for his birthday, I realized that a number of people ride their bicycles every day without the protection of a helmet.

      Due to cold winters across the country, riding has become increasingly dangerous as many roads have holes and are torn-up（磨损的）. Not everyone realizes that there are laws requiring the wearing of helmets in many places.

    Where I live, there has been a law in place since October 1, 1992 stating that cyclists of all ages are required to wear helmets. Unfortunately, accidents can happen to the best of riders. My dad has been a cyclist for many years, and he often rides around my county and to Rockland Lake State Park.

    One afternoon, as he was just entering the park, he lost control of his bicycle and flew off and landed on a nearby patch of grass, breaking his helmet into pieces and losing consciousness（知觉）. When he was just awakening, a lovely couple found him and brought him back to our house, where he attempted to recall the events leading up to his fall. Later that day, a CAT scan showed that he had a concussion (脑震荡). That evening, while my dad was showing me the pieces of his broken helmet, we both came to a shocking realization.

    If he had not worn his helmet, he probably would have cracked his skull and perhaps died. Today, when my dad and I go out cycling, the wearing of our helmets is not even a question. Regardless of age, everyone should wear a helmet whenever they get on a bicycle.

    After some blood tests, Dr Stubs stood before me, a tall man, but short on personality and sporting a cold expression. You have systemic lupus, he said matter-of-factly. "Lupus," he continued, "is an auto-immune disease and …." I remember certain details but mostly I remember him talking about children. "Children are no harm. But childbirth would jumpstart additional symptoms that could be life threatening. You already have two kids anyway."

    As I got up to leave, shaken and drained, he said his parting words, "I would discourage any further research. There is no cure and nothing can prevent its progression."

    Still, I did research lupus and its symptoms tiredness and joint pain-were both consistent with what I was experiencing. And eventually some major organs could be affected, causing shutdown and possibly death.

    I studied and found out that echinacea had a record in making immune system stronger. I decided that along with the plant I would strengthen my mindset by immersing myself in my family with my one-year-old son and three-year-old daughter.

    After another visit, I decided never to go back to Dr. Stubs. How could one endure repeatedly hear desperately words coming from an emotionless mouth even though they were truth? The years passed. When I would feel tired and achy I pulled support from my children and their laughter.

    Finally, after eight years, I went to Dr. Kirstein who was recommended by a friend. She stood there holding my hand and looking into my eyes warmly.

    "So let's talk a little

    Instantly my defenses were down. Before I knew it, she had me running on and on about my children, my husband, my life and dreams. I told her about all the meaningful activities I was involved in, those things I might have never done without the disease.

    After several follow-up tests, and greater research into my family history, Dr. Kirsteincame to conclusive answer. I did not have systemic lupus. There must be something wrong with the initial tests 8 years before.

    I didn't know whether I should jump for joy or scream because I had been living the last eight years in fear of a fatal disease. But then I realized that I had been living every day, not so much in fear, but happiness Even day was a gift and I knew it.

    There's been a lot of talking about white-and-blue collar workers, and you may have even heard of gold collar workers, but lately a new color of collar is making its way into China's urban vernacular(土话)—green. Green collars say no when work is life and life is work. They choose to get out of the fast lane(车道), and explore new ways of living "green".

    Living green doesn't mean someone is working as an environmentalist, biologist or scientist. Instead it is more of a lifestyle choice. A typical green collar is well educated like a white-collar but physically tough like a blue-collar, likely born in the 70s or 80s of the last century and living in one of China's big cities, with a monthly income well above 5,000 yuan(about US $700).

    The life of a green collar may go something like this: Turn off the mobile phone after work, eat only healthy food rich in vitamins, go on hikes every weekend, and like to help the underprivileged.

    Green collars even have their own club. In Beijing, the Green Collar Club is for people who share a "be happy, healthy and helpful" spirit. The club often holds charity parties and uses the donations for environmental protection and poverty relief(摆脱贫困) projects in China.

    "They are successful in their careers, but do not miss the pleasures in life. They have a lot of money, but do not fall slave to it." said Zuo Shiguang, one of the founding members of the club.

    Alexa is a form of artificial intelligence, or Al for short. Many people start their mornings by asking Alexa for the weather forecast or the latest news. A device (设备)that houses Alexa can also play music from your favorite playlists, keep a shopping list, order takeout food, answer questions, send voice messages and even run "smart" home controls.

    Training AI systems to respond to problems with human-like intelligence—and learn from their mistakes —can take months, or even years. Consider Alexa and similar software, such as Apples Siri. To do the tasks its human owners ask, these systems must make sense of and then respond to sentences such as, "Alexa, play my Ed Sheeran playlist" or "Siri , what is the capital of India?"

    Computers can't understand language as it is spoken by people. So AI researchers must find a way to help humans communicate with computers. The technology used to get computers to "understand" human speech or text is known as natural language processing. By natural language, computer scientists refer to the way people naturally talk or write. To teach an AI system a task like comprehending a sentence or responding to a person's last move in a board game, scientists need to feed it lots of examples.

    AlphaGO is an AI system designed by Google that has beaten a human champion, Lee Sedol, at the strategy(策略)board game Go. To train AlphaGo, Google had to show it 30 million Go moves that people had made while playing the game. Then AlphaGo used what it learned to analyze those plays as it played against different versions (版本)of itself. During this practice, the program came up with new moves —ones never seen in games between people.

    Computers, software and devices that are powered by AI can do much more, however, than just play board games and music. And one day they could make our life much easier and much more interesting.