Here is an astonishing and significant fact: Mental work alone can't make us tire. It sounds absurd. But a years ago, scientists tried to find out how long the human brain could labor without reaching a stage of fatigue (疲劳). To the amazement of these scientists, they discovered that blood passing through the brain, when it is active, shows no fatigue at all! If we took a drop of blood from a day laborer, we would find it full of fatigue toxins(毒素) and fatigue products. But if we took blood from the brain of an Albert Einstein, it would show no fatigue toxins at the end of the day.

    So far as the brain is concerned, it can work as well and swiftly at the end of eight or even twelve hours of effort as at the beginning. The brain is totally tireless. So what makes us tired?

    Some scientists declare that most of our fatigue comes from our mental and emotional(情绪的) attitudes. One of England's most outstanding scientists, J.A. Hadfield, says, “The greater part of the fatigue from which we suffer is of mental origin. In fact, fatigue of purely physical origin is rare.” Dr. Brill, a famous American scientist, goes even further. He declares, “One hundred percent of the fatigue of sitting worker in good health is due to emotional problems.”

What kinds of emotions make sitting workers tired? Joy? Satisfaction? No! A feeling of being bored, anger, anxiety, tenseness, worry, a feeling of not being appreciated—those are the emotions that tire sitting workers. Hard work by itself seldom causes fatigue. We get tired because our emotions produce nervousness in the body.

    Anki has introduced Cozmo, a little robot powered by an advanced artificial intelligence. Cozmo promises to be for more interactive（互动的）than any toy robot.

Cozmo, which can lie in your hand, has a “brain”—technically its CPU—that can process data amazingly fast. In addition, Cozmo has a playful personality. He's designed to react to emotions and even ask users to play with him.

    Cozmo is not the first interactive toy to reach the market nor is it the first robot toy. What sets Cozmo apart from the other “smart toys” is that it has greater play value than those toys, which can become repetitious all too quickly.

    “Every interaction with Cozmo is different, so you do not put up with repetitive play patterns and responses typically found with other preprogrammed robots,” explained Anki spokesperson Peter Nguyen. Because it has functionality that is similar to that of video games, Cozmo also can receive regular updates, which could extend its playability. Still, Anki has designed this toy to be just that: a toy. It's not an advanced computerized robot. Its software is app-based.

    Cozmo lacks the “traditional” human-like robot form factor（要素）of legs, arms, and a head. But Cozmo does have an OLED screen/face with blue eyes, which in fact were designed to help it connect with its user.

    “I'm glad my kids are already raised,” said Roger L. Kay, analyst at Endpoint Technologies Associates. “Otherwise, they might become more antisocial if their relationship with Cozmo is more satisfying than those with real people,” said Kay. “Cozmo might encourage kids to learn more about technology or even inspire them to try programming and similar studies,” said Charles King, analyst at Pund-IT.

    Yet this technology does promise to be more than a toy. “It's a pretty cool invention and might have further applications, for example in elder care,” suggested Kay.

    If you live in a big city, there are many thing to drive you crazy on your daily route, and it's not just overcrowded subway trains.

    Vicky Zhao is a mainlander working in Hong Kong. For her, one thing she can't put up with is people standing on the wrong side of the escalator(自动扶梯) in subway stations. "Escalators help us move faster and save time. It isn't a place to rest," the 24-year-old says. "I often see tourists block the way with their suitcases or chatting on the escalators during rush hours. It annoys me to no end."

    Admitting she is not the patient type, Zhao says things are much better in Hong Kong than in cities on the mainland where "stand right, walk left" signs are often ignored.

    The logic behind the "stand right, walk left" escalator etiquette(礼仪) seems obvious. Even though you may want to catch your breath while you're transported up or down, you should still consider others and leave enough space for people in a hurry, so that they can run and catch the train.

    Many cities' escalators, including London's and Beijing's, use the "stand right, walk left" system to speed up the flow of people. (Australia is an exception and you should stand on the left side instead.) But some cities discourage people from moving on escalators out of safety reasons. In Hong Kong's subway stations there are regular announcements asking people to "stand still" on escalators. Even so, most people in this fast-paced city observe the "stand right, walk left" etiquette.

    But the people who stand on escalators defend themselves by telling the walkers not to be so impatient. The BBC quotes one stander as saying: "If the person is in such a rush, why not just take the stairs? Even when the escalator is packed and there's nowhere to move, I see these same people complaining about not being able to pass."

    Whatever the escalator etiquette is in the place you live or visit, do what most people are doing and always be mindful of others: leave enough space between each other, don't stay at the end of the escalator, and if someone is blocking your way, a simple "excuse me" is enough.

Larry was on another of his underwater expeditions(探险)but this time, it was different. He decided to take his daughter along with him. She was only ten years old. This would be her first trip with her father on what he had always been famous for.

    Larry first began diving when he was his daughter's age. Similarly, his father had taken him along on one of his expeditions. Since then, he had never looked back. Larry started out by renting diving suits from the small diving shop just along the shore. He had hated them. They were either too big or too small. Then, there was the instructor. He gave him a short lesson before allowing him into the water with his father. He had made an exception. Larry would never have been able to go down without at least five hours of theory and another similar number of hours on practical lessons with a guide. Children his age were not even allowed to dive.

After the first expedition, Larry's later diving adventures only got better and better. There was never a dull moment. In his black and blue suit and with an oxygen tank fastened on his back, Larry dived from boats into the middle of the ocean. Dangerous areas did not prevent him from continuing his search. Sometimes, he was limited to come to a cage underwater but that did not bother him. At least, he was still able to take photographs of the underwater creatures.

    Larry's first expedition without his father was in the Cayman Islands. There were numerous diving spots in the area and Larry was determined to visit all of them .Fortunately for him, a man offered to take him around the different spots for free. Larry didn't even know what the time was, how many spots he dived into or how many photographs he had taken. The diving spots afforded such a wide array of fish and sea creatures that Larry saw more than thirty varieties of creatures.

Larry looked at his daughter. She looked as excited as he had been when he was her age. He hoped she would be able to continue the family tradition. Already, she looked like she was much braver than had been then. This was the key to a successful underwater expedition.

    America's top education official says many schools are spending too much time teaching the "basics"—reading, math and writing. It might seem opposite to what educators have been promoting. But U.S. Education Secretary John King says children really deserve access to a well-rounded education that includes music and arts because it will help them go into being well-rounded, well-educated persons.

    King spoke about his own education when explaining why schools need to teach more than math, reading and writing.

    King grew up in New York. Both his parents died when he was quite young. In his house, things were often crazy and frightening. It was his teacher, Mr. Osterwei, who helped him escape his difficult life. Quite often, the teacher took him and his classmates to the theater, the zoo, the ballet and famous Museum of Natural History. "Those were powerful, life-changing experiences, "King says. King graduated from Harvard University. He received his law degree from Yale University. He took charge of New York State public schools from 2011-2015. The U.S. Senate approved him as Education secretary last month.

    Many schools spend almost all funding on the "basics" because they lack money for other subjects, King says. Or they want students to do better on tests used to compare student performance.

    Students need to connect their studies and things that matter to them personally, such as music if they are to become "sophisticated(水平高的) thinkers". A 2013 report by UNESCO says today's world needs people able to solve new and unusual problems. It says arts can help students find those answers. In the report, UNESCO said teaching the arts in China, South Korea and Japan is different.

    From that in many Western countries, the emphasis(重点) in those three countries is "on joyful experiences and children's interests." In the West, educators are more likely to connect the arts to reading, writing and math. A 2014 report tried to compare how well countries teach children how to solve problems. It found Singapore, South Korea, Japan, China, Canada, Australia and Finland with the highest scores for 15-year-olds. Singapore led the way with a score of 562 out of a possible 1, 000. The average score was 500. The United States had a score of 508.

    The Top 4 Restaurants of 2018

    No. 4

    Kuya Ja's Lechon Belly (4 stars): 5268-H Nicholson Lane, Rockville, Md. 240-669-4383. kuyajas. com.

    Open: Breakfast, lunch and dinner Wednesday through Monday; breakfast and lunch Tuesdays.

    Prices: Sandwiches, bowls and combination meals, $ 6.99-$ 12.59.

    Sound check: 74 decibels（分贝）/ Must speak with raised voice.

    No. 3

    Little Havana（41/2 stars): 3704 14th St. NW. 202-758-2127. littlehavanadc.com.

    Open: Dinner daily.

    Prices: Sandwiches and mains $ 9-$ 25.

    Sound check: 70 decibels / Conversation is easy.

    No. 2

    Three Blacksmiths (41/2 stars): 20 Main St., Sperryville, Va. 540-987-5105. Three black smiths.com.

    Open: Dinner Thursday—Saturday.

    Prices: Small plates $ 5 - $ 20, large plates and family-style plates $ 24 - $ 94.

    Sound check: 81 decibels / Extremely loud.

    No. 1

    Momofuku（5 stars): 1090 I St. NW. 202-602-1832. ccdc.momofuku.com.

    Open: Lunch Monday through Friday, dinner daily, breakfast Saturday and Sunday.

    Prices: Small plates $ 5 - $15.

    Sound check: 75 decibels / Must speak with raised voice.