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Five years ago, when I taught art at a school in Seattle, I used Tinkertoys as a test at the beginning of a term to find out something about my students. I put a small set of Tinkertoys in front of each student, and said:"Make something out of the Tinkertoys. You have 45 minutes today - and 45minutes each day for the rest of the week."

   A few students hesitated to start. They waited to see the rest of the class would do. Several others checked the instructions and made something according to one of the model plans provided. Another group built something out of their own imaginations.

   Once I had a boy who worked experimentally with Tinkertoys in his free time. His constructions filled a shelf in the art classroom and a good part of his bedroom at home. I was delighted at the presence of such a student. Here was an exceptionally creative mind at work. His presence meant that I had an unexpected teaching assistant in class whose creativity would infect(感染) other students.

Encouraging this kind of thinking has a downside. I ran the risk of losing those students who had a different style of thinking. Without fail one would declare, "But I'm just not creative."

"Do you dream at night when you're asleep?"

"Oh, sure."

"So tell me one of your most interesting dreams." The student would tell something wildly imaginative. Flying in the sky or in a time machine or growing three heads. "That's pretty creative. Who does that for you?"

"Nobody. I do it."

"Really-at night, when you're asleep?"

"Sure."

"Try doing it in the daytime, in class, okay?"

    The Canadian red and white maple leaf (枫叶) flag is officially called the National Flag of Canada. The Canadian flag shows a stylized red maple leaf with 11 points on a white background, with red borders down each side. The Canadian flag is twice as long as it is wide. The white square containing the red maple leaf is the same width as the flag.

    The red and the white used in the National Flag of Canada were proclaimed the official colors of Canada in 1921 by King George Ⅴ. Although the maple leaf did not have its official status as a symbol of Canada until the announcement (宣告) of the national flag in 1965, it had historically been used as a Canadian symbol, and was used in 1860 in decorations for the visit of the Prince of Wales to Canada. The 11 points on the maple leaf have no special significance.

    In the early days，the Royal Union Flag，or the Union Jack, was still flown in British North America. In 1925 and again in 1946, the Canadian Prime Minister Mackenzie King tried to get a national flag of Canada adopted, but failed. In 1964，Prime Minister Lester Pearson appointed a 15-member, all-party committee to come up with a design for a new flag. The committee was given six weeks to complete its task.

    The committee studied 2,000 submitted(提交的) designs as well as 3,900 that had been gathered as a result of the 1946 committee's study. Those designs with a chance of being accepted were given to the full committee for further study.

    The suggestion of a red and white single maple leaf design for the Canadian flag came from George Stanley, a professor at the Royal Military College. After a heated discussion, they finally decided on his suggestion.

    More than 90 years has passed since Hollywood's official film organization first proposed plans to build its own museum. Those plans are finally becoming a reality, with the Academy Museum of Motion Pictures set to open in 2019.

    The project is underway at the site of a historic Los Angeles department store built in 1939. Museum officials say visitors will be able to “experience the magic of cinema” by learning about all parts of the film-making process.

    Film historian Kerry Brougher has been named directors of the museum. Brougher says the museum will include 12 million photographs and 80,000 screenplays as well as props（道具）, costumes and other objects from famous films. The Academy Museum will also feature Oscar statuettes（小雕像）donated by actors who won the awards.

    Brougher says the museum is designed to make visitors feel like they are in a movie, too, with many interactive experiences. “You won't necessarily know what's coming next, '' he adds. “You'll be in environments sometimes that make you feel like you've gone back to the past and that you're in the area that you're actually exploring.” He adds that visitors may even get the chance to walk down a red carpet and accept their own Academy Award.

    Currently, Hollywood only has a few possibilities for visitors. They can go along the Walk of Fame and visit movie studios or see the Dolby Theater, where the Oscars are presented. But beyond these, movie fans have limited possibilities.

    Eric Garcetti, the mayor of Los Angeles says the Academy Museum will provide visitors the chance to experience many different parts of the film industry all in one place. Garcetti notes the museum will also serve the hundreds of thousands of local people working in film-related businesses. He says they, too, will finally be able to visit a place that celebrates their own Hollywood movie industry.

    In Europe, there is no escape for those who do not appreciate art and architecture(建筑). It is a heaven for people who want to feel like they have been transported to famous historical time periods from America. For me, Europe was a complete contrast from America. London and France had a more royal feel than New York, and Rome felt more ancient. I wasn't just on a different continent; it felt like I was in a different century.

    My parents and I visited London, Paris and Rome this summer in celebration of the end of my high school experience. It was supposed to be a break from a life as busy as a bee in New York, the constant stress, the crowded subway rides, and the weary body that had accompanied me for the last four years. It was an opportunity to appreciate Europe the way I couldn't do it just by reading history books.

    My favorite parts of London were the Tower of London and the Churchill War Rooms. As a site of past executions(刑场), the Tower of London displayed punishing devices from the 16^th and 17^th century and told stories of various members of the royal family who had ever been imprisoned in the tower, some even imprisoned by their own family members when they were seen as a threat to the crown. Besides that, I also got to see the royal family's crown jewels, amazingly beautiful.

    The Churchchill War Rooms, though very different from the Tower of London, were also spellbinding from a historic perspective. I am not a history fan, but I enjoy museums, and I took fancy in the Churchchill Museum inside the War Rooms that detailed the events of Churchchill's life and World War II. Everything I saw in it built up his life from his childhood to his last years, creating a three-dimensional Churchchill in my mind who was a person just like myself. He longed for more, he made mistakes, he experienced loneliness and sadness. But he had also done some remarkable things like uniting Britain during World War II.

    Our rewarding trip ended in Rome a couple of days later.

    Are your eyes irritated, dry, watery, blurry, seeing double or sensitive to light, and do your back and neck ache? If so, you are likely one of many people today who suffer from digital eyestrain, also called computer-vision syndrome.

    Eyestrain is often related to the amount of exposure to screens, the distance from eyes to screens and the use of multiple screens simultaneously. However, studies have also shown that the blue light produced by digital devices today reaches further into the eyes than other kinds of light. This light actually assists attention during the day but can result in interrupted sleep patterns at night.

    Scientists have also said that eyestrain is not a necessary evil, even in a modern world that revolves around technology. Changing some simple details about your relative position to screens, such as staying about 60 centimeters away, will help. Also, avoid overhead and other direct sources of light, and use shaded lamps and window blinds while looking at digital devices instead.

    Beyond the way that relates to digital screens, there are also ways to change how you view screens that are helpful in combating eyestrain. To begin with, your computer screen should be high-resolution(高清的), at least 50 centimeters wide diagonally and may require a screen filter to decrease reflections. Also, be aware that "computer glasses", which cut down glare and blue light, are available and those contact lenses can increase the risk of eyestrain.

    Besides, to reduce your risk for computer-vision syndrome and neck, back and shoulder pain, take frequent breaks during your computer workday. Many workers take only two 15-minute breaks from their computer throughout their day. According to a recent study, discomfort and eyestrain are significantly reduced when computer workers take four additional five-minute "mini-breaks" throughout their workday. And these additional breaks don't reduce the workers' productivity.

    Finally, many of us fall into bad habits while using digital screens that only worsen the effects of eyestrain. While viewing digital screens, many people blink one third less often than they usually do. Place a reminder on your computer to "blink" so that your eyes don't dry out. Also, rest your eyes' focusing muscles by using the 20-20-20 rule: Every 20 minutes, focus on something 20 feet away for 20 seconds.

    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.