Johnny Smith was a good math student at a high school. He loved his computer. He came home early every day, then he worked with it till midnight. But Johnny was not a good English student, not good at all. He got an F in his English class. One day after school Johnny joined his computer to the computer in his high school office. The school office computer had the grades of all the students: the math grades, the science grades, the grades in arts and music, and the grades in English. He found his English grade. An F! Johnny changed his English grade from an F to A. Johnny' parents looked at his report card. They were very happy.

    "An A in English!" said Johnny's Dad. "You're a very clever boy, Johnny."

    Johnny is a hacker (黑客). Hackers know how to take informationfrom other computers and put new information in. Using a modem, they join their computers to other computers secretly. School headmasters and teachers are worried about hackers. So are the police, for some people even take money from bank computer accountand put it into their own ones. And they never have to leave home to do it! They are called hackers.

    The sharing economy, represented by companies like Airbnb or Uber, is the latest fashion craze. But many supporters have overlooked the reality that this new business model is largely based on escaping regulations and breaking the law.

    Airbnb is an Internet-based service that allows people to rent out spare rooms to strangers for short stays. Uber is an Internet taxi service that allows thousands of people to answer ride requests with their own cars. There are hundreds of other such services.

    The good thing about the sharing economy is that it promotes the use of underused resources. Millions of people have houses or apartments with empty rooms, and Airbnb allows them to profit from these rooms while allowing guests a place to stay at prices that are often far less than those charged by hotels. Uber offers prices that are competitive with standard taxi prices and their drivers are often much quicker and more trustworthy.

    But the downside of the sharing economy has gotten much less attention. Most cities and states both tax and regulate hotels, and the tourists who stay in hotels are usually an important source of tax income. But many of Airbnb's customers are not paying the taxes required under the law.

    Airbnb can also raise issues of safety for its customers and trouble for hosts' neighbors. Hotels are regularly inspected to ensure that they are not fire traps and that they don't form other risks for visitors. Airbnb hosts face no such inspections.

    Since Airbnb is allowing people to escape taxes and regulations, the company is simply promoting thefts. Others in the economy will lose by bearing an additional tax burden or being forced to live next to an apartment unit with a never-ending series of noisy visitors.

    The same story may apply with Uber. Uber is currently in disputes over whether its cars meet the safety and insurance requirements imposed on standard taxis. Also, if Uber and related services flood the market, they could harm all taxi drivers' ability to earn a minimum wage.

    This downside of the sharing needs to be taken seriously, but that doesn't mean the current tax and regulatory structure is perfect.

    What do you use to unlock your cellphone? A password? A fingerprint? Or simply a glance?

    On September 12, 2017, Apple introduced its iPhone X, which has an eye-catching feature—Face ID.

    With Face ID, Apple says, you can unlock your new iPhone by just looking at it. It is powered by a so-called TrueDepth camera system built into the front of the iPhone X.

    When the camera system sees a person's face, it uses 30,000 unseen dots to “map” the shape and outline of the face. A mathematical model of the face will then be created and stored in the phone.

    The next time the person looks at the iPhone X, the same dots are mapped onto his or her face and compared to the stored model. If the two match, then the phone unlocks. This happens in less than a second.

    Apple says the system is smart. If you change your hairstyle, put on sunglasses or makeup, or use the phone in the dark, Face ID still works.

    Although the technology sounds fancy, there are still concerns. For example, will Face ID work for twins?

    According to Apple, the chance of others to unlock your iPhone X using Face ID is one in a million. Face ID can tell the difference between twins, but the error rating（出错率）rises. So one would need to set a password then.

    Apple also emphasizes that Face ID only unlocks when you stare at it. It is what Apple calls “attention aware”. So the phone won't unlock if you are just glancing at the phone for the time. It won't work either if someone puts the phone at your sleeping face or your photo.

    A team of engineers at Harvard University has been inspired by Nature to create the first robotic fly. The mechanical fly has become a platform for a series of new high-tech systems. Designed to do what a fly does naturally, the tiny machine is the size of a fat housefly. Its mini wings allow it to stay in the air and perform controlled flight tasks.

    “It's extremely important for us to think about this as a whole system and not just a bunch of individual components (零件),” said Robert Wood, the Harvard engineering professor who has been working on the robotic fly project for over a decade. “The added difficulty with such a project is that actually none of those components are off the shelf and so we have to make them all on our own,” he said.

    They engineered a series of systems to start and drive the robotic fly. “The seemingly simple system which just moves the wings has a number of individual components, each of which individually has to perform well, and then has to be matched well to everything it's connected to,” said Wood. The flight device was built into a set of power, computation, sensing and control systems. Wood says the success of the project proves that the flying robot with these tiny components can be built and manufactured.

    Wood says the design offers a new way to study flight mechanics and control at insect- scale. Yet, the power, sensing and computation technologies on board could have much broader applications (应用). “You can start thinking about using them to answer open scientific questions, you know, to study biology in ways that would be difficult with the animals, but using these robots instead,” he said. “So there are a lot of technologies and open interesting scientific questions that are really what drives us on a day to day basis.”

    As any plane passenger will confirm, a crying baby is almost impossible to ignore, no matter how hard you try. Now scientists believe they may have worked out why. A baby's cry pulls at the heartstrings(扣人心弦) in a way while other cries don't, researchers found.

    Researchers found that a baby's cry can trigger unique emotional responses in the brain, making it impossible for us to ignore them—whether we are parents or not. Other types of cries, including calls of animals in great pain, fail to get the same response—suggesting the brain is programmed to respond specifically to a baby' cry.

    A team of Oxford University scientists scanned the brains of 28 men and women as they listened to a variety of calls and cries. After 100 milliseconds—roughly the time to blink(眨眼)—two parts of the brain that respond to emotion lit up. Their response to a baby's cry was particularly strong. The response was seen in both men and women—even if they had no children.

    Researcher Dr Christine Parsons said, “You might read that men should just notice a baby and step over it and not see it, but it's not true. There is a special processing in men and women, which makes sense from an evolutionary view that both men and women would be responding to these cries.” The study was in people who were not parents, yet they are all responding at 100ms to these particular cries, so this might be a fundamental response present in all of us regardless of parental status.

    Fellow researcher Katie Young said it may take a bit longer for someone to recognize their own child's cries because they need to do more “fine-grained analysis”. The team had previously found that our reactions speed up when we hear a baby crying. Adults performed better on computer games when they heard the sound of a baby crying than after they heard recordings of adults crying.

    I always dreamed of studying abroad, to learn at a world﹣class university while further exploring the grounds on which these nations achieved new milestones of development with each passing day.

    To study abroad after my graduation, I could not stop seeking my dream. To take the first step, I did some brainstorming and explored opportunities on the Internet and finally decided to go for China. There were a number of reasons behind it﹣its advanced education system and thousands of centuries of rich culture inspired me to study there. The primary one was my curiosity how a nation has left many nations behind in a short time at its fast pace of development.

    So just like that, I applied, along with some of my friends, for a master's degree program at Communication University of China. I was the only one who got selected in the said program and in addition, the Chinese Scholarship Council sponsored all of my expenses. This good news was welcomed by my family.

    This is my seventh month in Beijing. In my experience so far, one thing that appeared to be missing was the internship（实习） which I tried to find because I want to work here after completion of my studies. After some struggles I was lucky enough to get the opportunity to work as an intern with the Center for China and Globalization（CCG）. It's very exciting to work on their team as a researcher. Now I can proudly say that my decision to choose China as a study destination was the best decision I have ever made.