“Community” is not a concept that is easy to define (定义) . In this essay I will examine what turns individuals into a community, and discuss some different types. I will also look at what all communities have in common, the benefits they offer and draw conclusions about their increasing importance.

    The word “community” may make you think of traditional communities in the developing world, where large families live together. We may also imagine the neighbours as people who are happy to help out whenever it is needed. The stereotpical(老套的) view is that of a village, where people have little but can feel very rich because everyone takes responsibility for the welfare of the others.

    On the other hand, there are other types of communities: ultramodern(超现代的) ones, where the community members are unlikely to have actually met each other. These are online communities, where people blog or chat about particular issues that are important to them. They come across others on websites and may develop a relationship there with like-minded people, discussing the same topics. The view is often that these are artificial connections between people who are, in effect, still isolated(孤立的) strangers.

    In reality, the connections are real. Moreover, there are many types of communities in between these extremes: people who join clubs, who sign up with voluntary, political or other organizations, or who take part in group discussions in their local area. They may be campaigning about issues or simply getting together for companionship and support.

    Human beings are social by nature, so it should not be a surprise that we organize ourselves in groups. However, there is more going on: these groups provide something that we cannot achieve on our own. The main benefit of being part of a larger group is strength in numbers. For example, we can access and share more information, we can take part in team sports, we can complain and campaign more effectively and even if we are just having a chat, online or in person, we can feel supported in whatever we do.

    Whatever forms communities take, what defines them is the sense of identity and safety that they provide for their members: the knowledge that there are people who we have something in common with and who can be relied on when we need each other.

Mark Twain's First Money

      Mark Twain was asked one day if he could remember the first money he ever earned. He thought a long time and then said, "Yes, it was at school. I can remember everything about it. School boys in those days did not take good care of their chairs and desks. There was a rule in our school that if anyone damaged his desk or chair, he would have to pay five dollars or the teacher would beat him in front of the whole school."

    "One day I damaged my desk in some way, I had to pay five dollars or be beaten before the whole school. My father said it would be too bad to have our family disgraced in front of the whole school. He agreed to give me five dollars to hand over the teacher. But before he gave me the money, he took me upstairs and gave me a beating."

    "But as I had one beating and I decided I would take another beating at school and keep the five dollars. So that's what I did. That was the first money I ever earned."

    Angad Rekhi, a graduate student and an assistant professor of electrical engineering, has developed a wake-up receiver. This wake-up receiver has many potential applications, particularly in designing the next generation of net worked devices, including so called "smart" devices that can communicate directly with one another without human intervention (介入).

    Once attached to a device, a wake-up receiver listens for a unique ultrasonic（超声波）pattern that tells it when to turn the device on. It needs only a very small amount of power to maintain this constant listening, so it still saves energy overall while extending the battery life of the larger device. A well-designed wake-up receiver also allows the device to be turned on from a significant distance.

    Given the increased interest in networked devices, researchers and industry organizations are starting to define what features and techniques will become standard. Regardless of whether this ultrasound wake-up receiver is among these standard designs, it is likely wake-up receivers of some kind will be combined into commercial applications soon.

    By comparison, the ultrasound wake-up receiver requires a battery but has much greater range than the wirelessly powered devices, while still maintaining a long lifetime due to extremely low power draw. These two technologies-wireless power and wake-up receivers-would likely serve different purposes but both indicate at a turning point in devices that make up the Internet of Things.

    "In light of a long-promised future where interconnected, autonomous, widespread and unremarkable technologies make life easier, the networked devices available now, like video doorbells and app-enabled lights, seem like rather slight advances." the researchers said. They believe technologies like theirs could help cross the gap between the Internet of Things as we know it and the Internet of Things at its best-whatever that may be.

    When I was growing up, Mother's Day was as important as Christmas.

    The energy around the house was always positive（积极的）, mostly thanks to my father who made sure that his kids appreciated their mother, We would clean the house, and Mum got breakfast in bed in the morning and didn't have to lift a finger all day. And in the evening, we went to a restaurant for a traditional Mother's Day dinner.

    What I learned from my father over the years, was that no matter what, he always put my mother before himself. He absolutely loved her and never let her forget that. And from my parents, I learned a thing or two about how to love.

    I maintain（保持） my father's Mother's Day tradition with my wife. Growing up, I learned that showing affection to the woman you love or who gave birth to you is an important part of life. You see, it goes both ways, and the love you have for your mother comes back to you again and again.

    Believing that and feeling it when you can may keep you from being lonely, even if your mum isn't close by or has passed away. There are a number of us who no longer have a mother in our lives, and truth be told, there are often times when I wish my mum were still here to comfort me. So instead, I remember the times she did just that. It makes me smile, and somehow, those memories of a more simple and loving life give me the comfort I'm looking for.

    My wife's mother is still around, however, and it's great to have that "mother energy" in my life still. Having this relationship with my mother-in-law is nice because it gives me someone to be there for on Mother's Day, and any other day of the year.

    If you are mum-less, you too should find a deserving woman in your life and celebrate Mother's Day with her. If you don't know anyone, there are plenty of lonely mums in rest homes who would enjoy your company for a couple of hours. The visit will make both of your days, and perhaps your lives, a little bit better.

    If you were an exchanged student in New York City, one day your math teacher gave you following questions as your homework, please write down your answers.

    Ⅰ.A company sold a product for α dollars in 1990. The price of the product would increase by 2.5% every year.

    Ⅱ.A man needs to make 3 curtains. The cloth which is used to make curtains sells for $8.00 per meter and can be purchased only by the full（完整的） meter. The length of cloth required for each curtain is 1.6 meters.

    Ⅲ.A pet store sells only dogs and cats. In March, the store sold twice as many dogs as cats. In April, the store sold twice the number of dogs that it sold in March, and three times the number of cats that it sold in March.

    If you're looking at diving for the first time in Papua New Guinea, believe everything you have read about our world-class waters.

    Called the "underwater photographer's paradise", we've got many international awards for underwater photography taken here. In our oceans you'll see up to twice as many marine species as the waters of the Red Sea and up to five times as many as the Caribbean. Our waters enjoy a huge diversity of dive sites, including reefs, coral walls, seagrass beds, and wreck dive sites (ships, aircraft and submarines!).

    Must see

    Dive down to a fully complete Japanese fighter plane in Kimbe Bay, known also for soft coral and unusual creatures.

    Experience "Muck Diving", which puts Papua New Guinea on the map, in Milne Bay.

    Explore our surfing destinations from October to April. Relatively new to international surf enthusiasts, our breaks at Vanimo, Wewak, Madang and Kavieng are quickly becoming known for being uncrowded, challenging and entertaining for days!

    Want to book a "Muck Diving"? Call 00675-374.

    Want to dive to see fighter plane? Call 00675-325.

    Where to stay

    Papua New Guinea has accommodation to suit every budget and need. From privacy-protected hideaways to family-friendly escapes, book your business package or luxury resort knowing you'll be well looked after.

    Want to find a suitable hotel? Call 00677-366.

    Further information

    Dive coaches offer both land-based (one day, three dives) and live-aboard dive tours (7-10 days, up to five dives a day).

    The average water temperature varies from 25℃ along the edge of the Coral Sea to 29℃in the Bismarck Sea.

    You can dive in Papua New Guinea all year round, with the high season generally from May to November.

    Want to get yourself a professional dive coach? Call 00652-392.