Do you know how it is when you see someone yawn and you start yawning too? Or how hard it is to be among people laughing and not laugh yourself? Well, apparently it's because we have mirror neurons (神经元）in our brains.

    Put simply, the existence of mirror neurons suggests that every time we see someone else do something, our brains imitate (模仿)it，whether or not we actually perform the same action. This explains a great deal about how we learn to smile, talk, walk, dance or play sports. But the idea goes further： mirror neurons not only appear to explain physical actions _y they also tell us that there is a biological basis for the way we understand other people.

    Mirror neurons can undoubtedly be found all over our brains, but especially in the areas which relate to our ability to use languages, and to understand how other people feel. Researchers have found that mirror neurons relate strongly to language. A group of researchers discovered that if they gave people sentences to listen to ( for example ："The hand took hold of the ball" ) , the same mirror neurons were triggered as when the action was actually performed (in this example, actually taking hold of a ball).

    Any problems with mirror neurons may well result in problems with behavior. Much researeh suggests that people with social and behavioral problems have mirror neurons which are not fully functioning. However, it is not yet known exactly how these discoveries might help find treatments for social disorders.

    Research into mirror neurons seems to provide us with ever more information concerning how humans behave and interact(互动）.Indeed, it may turn out to be the equivalent (相等物）for ncurosciencc of what Einstein's theory of relativity was for physics. And the next time you feel the urge to cough in the cinema when someone else does--well，perhaps you'll understand why.

    February 14th is Valentine's Day! In China, it is only a day for boyfriends and girlfriends. But my teacher and my friends in America told me that Valentine's Day is a public day.

    This was my first Valentine's Day in America. I didn't understand the customs clearly. Maybe I didn't need to send any gifts. I watched others to see what they did, so next time I can understand.

    On that day, when we began the reading class, Mr. Peters gave every student some chocolates and said, “Happy Valentine's Day!” I was very happy. The teacher gave his students gifts and blessings! I never saw that in China. Maybe American teachers are very different. I didn't buy a gift for the teacher, so I owed a gift to the teacher. Anyway, I want to say, “Thank you teacher, and I'm sorry.”

When we had a break, one of my classmates gave me a Pokemon card. It was very funny. I felt we were children. I thought I owed a gift again, but I felt thankful. It was another gift, but it was from my new classmate.

    When we were moving to our grammar class, suddenly I heard someone calling me, “Shelly!” I stopped. Another classmate who had only been in our class one day gave me some chocolates. She said, “These for you and your friends. Have a good day!” I was looking at her leaving and thinking she spoke Arabic. We were in the same class only one day, but now we are friends. That's very good, but I owed a gift again.

    When I came home, my Chinese friend sent some roses and chocolates. I was surprised and happy because I had never received roses in my past life, but I hoped it was the last gift. I didn't want to owe more gifts.

    Our family loves the snow and cheers at the first good storm of the season. While others may think of Florida, we dream of a cabin vacation in New York's Allegany State Park.

    One particular trip, I recall, was just a bit more memorable than the rest. What we now refer to as the snow pants incident began accidentally enough. My husband, Bernie, and our 2-year-old daughter, Faith, were building a snow fort while I sledded down a nearby slope.

On the way back up from one trip, I saw a small stone tumbling down the track I had just made. I was puzzled, since all the other rocks were buried under several feet of snow, as I stood and wondered about the stone—it jumped! This was no stone. This was a mouse.

    Now, I love nature, but that doesn't include mice. I loudly protested the invader, and Bernie, coming to my rescue, assured me that this was not a mouse but a mole, as if that mattered. A mouse or a mole I still didn't like it.

    Bernie and I stood for a few minutes watching the creature disappear from the path into the furry white and come back out again. But soon it disappeared and I headed up the hill again.

    Shortly after I left, my husband screamed out, saying that the mole had gone up the leg of his snow pants. You have to understand Bernie can be quite a joker, and I smelled a rat. Not wanting to be a sucker and fall for another one of his jokes, I laughed it off. When he started running for the cabin, though, I stopped laughing and decided maybe this was for real.

    “Don't you dare take that thing into the house!” I yelled. But like a flash, Bernie was already dashing through the cabin's front door, with his snow pants, the mole and all. If it were me, I'd have been down to my long underwear right there in the snow without a second thought.

A few minutes later Bernie appeared. We relished the rest of our winter vacation, drinking lots of hot chocolate, sitting beside the fireplace and admiring nature—from a safe distance.

    Throughout much of human history, man has been the measure of many, if not all, things. Lengths were divided up into feet and smaller units from the human hand. Other measures were equally characteristic. Mediterranean traders for centuries used the weight of grains of wheat to define (定义) their units of mass. The Romans used libra, forerunner of the pound, by referring to the weight of a carob (角豆树) seed.

    The sizes of similarly named units could also differ. The king's foot, used in France for nearly 1, 000 years after its introduction by Charlemagne in around 790 AD, was, at 32.5cm, around a centimeter shorter than the Belgic foot, used in England until 1300.Greek, Egyptian and Babylonian versions of water in a fixed container varied from one another by a few kilos, Nor was there agreement on such things within countries. In France, where there was no unified (统一的) measurement system at the national level, the situation was particularly terrible. The lieue (former measure of distance), for example, varied from just over 3 km in the north to nearly 6 km in the south.

    Although John Wilkins, an Englishman, first put forward a decimal system (十进制) of measurement in 1668, it was the French who in 1799 made it law. The Système International d'Unités (SI, or the metric system, as it is better known) developed from it and became the official measurement in all countries except Myanmar, Liberia and the United States. Now the International Bureau of Weights and Measures in Paris is set to give the metric system its biggest shake-up yet.

    At a meeting in Versailles, France, on November 16th, 2018, the world's measurement bodies are almost certain to approve a decision that will mean four out of the seven base SI units, including the kilogram, will follow the other three, including the metre, in being redefined in terms of the values of physical constants (物理常数).Each of the chosen constants has been measured incredibly precisely, which would mean that from May 20^th 2019 the constants will themselves be fixed at their current values for ever. Any laboratory in the world will then be able to measure, for example, the mass of an object as precisely as the accuracy of their equipment will allow.

    Bookstores are a traveller's best friends: they provide convenient shelter in bad weather, and they often host readings and other cultural events. Here is a look at the world's six greatest bookstores.

    Adrian Harrington—since 1971. Rare books; rare first editions; leather—bound sets and general antiques (古玩). Address: 64A Kensington Church Street, Kensington, London, England, U.K.

    Another Country— Kreuzberg, Berlin, Germany. Another Country is an English language second-hand bookshop which is mostly used as a library. They have about 20,000 books that you can buy or borrow. Some regular events are held at the shop, such as readings, cultural events, social evenings and film nights.

    Atlantis Books—Oia, Santorini, Greece. Atlantis Books is an independent bookshop on the island of Santorini, Greece, founded in 2004 by a group of friends from Cyprus, England, and the United States. Throughout the year it has hosted literary festivals, film screenings, book readings, and good old-fashioned dance parties.

    Bart's Books—Ojai, California, U. S. A. "The World's Greatest Outdoor Bookstore", a bookstore founded by Richard Bartinsdale in 1964. Shelves of books face the street, and regular customers are asked to drop coins into the door's coin box to pay for any books they take whenever the store is closed.

    10 Corso Como—Milan, Italy, Extensive selection of publication on art, architecture, design, graphics and fashion, along with a strong emphasis on photography. It was founded in 1990 in Milan, Italy, by Carla Sozzani.

    The Bookworm—A bookshop, library, bar, restaurant and event space, now with five locations in three cities in China—Beijing, Suzhou and Chengdu. The interconnecting rooms with floor-to-ceiling books on every wall are light and airy in summer, yet warm and comfortable in winter.

Max Du emerged victorious at the Canada-Wide Science Fair with his innovative project: an unmanned aerial vehicle (UAV) designed to assist individuals experiencing cardiac arrests. His ingenuity was sparked during the Christmas recess of the preceding year. "I received a recreational drone as a gift from my parents, yet I was unable to operate it aloft due to the snowy conditions," Max recounted. "Consequently, I experimented with it indoors, which led me to contemplate the potential for a drone to serve as an automated indoor apparatus that could render assistance to people in need."

Approximately 35,000 Canadians succumb to cardiac arrests annually, with the majority of these incidents occurring beyond the confines of a hospital, resulting in a survival rate of less than 10 percent. Max was convinced that a drone could provide more expeditious assistance and expedite the delivery of vital medical treatments, but to validate this hypothesis, he was compelled to construct the device himself.

The process of refining his drone spanned a period of six months, during which Max's parents had to tolerate the persistent buzzing and crashing of the machine within their domicile. With each innovative feature he devised, such as a telescopic appendage, the drone's overall mass increased, leading to frequent disassembly. This necessitated the procurement of an entirely new set of components. Max persevered, experimenting with more lightweight construction materials until he achieved a more harmonious equilibrium in his design.

Through a methodical process of iterative refinement, the 14-year-old prodigy ultimately perfected his invention. His drone is now capable of manipulating a door handle, navigating through the air, and alighting gently on the ground. An innovative, extendable arm can be deployed to either administer an injection or deliver a life-saving pharmaceutical to a patient. Additionally, an integrated camera facilitates real-time communication with an emergency response team, enabling remote monitoring of the patient's condition.

Max is intent on pursuing the acquisition of a patent to forge alliances within the healthcare sector and bring his invention to fruition. He dedicated his summer to the study of artificial intelligence at Stanford University in California, where he was one of only 32 young scholars chosen globally. Subsequently, he will proceed to the University of Pennsylvania to enroll in a collegiate-level robotics course before resuming his high school studies in September.