Tulips(郁金香) are the national flower of Iran and Turkey. The European name for the flower is a misuse of the Persian word for turban(头巾), a mistake probably arising in the common Turkish custom of wearing flowers in the folds of the turban. Alternatively, the misuse may have arisen because this eastern flower, when not yet in full bloom, looks like a turban. In Persia, to give a red tulip was to declare your love for someone. The black center of the red tulip was said to represent the lover's heart, burned to a coal by love's passion.

    Originally growing in the Ottoman Empire (present-day Turkey), tulips were imported into Holland in the sixteenth century. When Carolus Clusius wrote the first major book on tulips in 1592, they became so popular that the tulips in his garden were stolen from time to time. As the Dutch Golden Age grew, so did this colorful flower. They were commonly seen in paintings and at festivals. In the mid-seventeenth century, tulips even created the first economics bubble（泡沫经济）, known as “Tulip Mania”. At that time, tulips were so expensive that they were used as money until the market for them crashed.

    Today, Holland is still known for its tulips and other flowers, often sincerely called “the flower shop of the world.” Tulips are planted in great fields of beautiful color, and transform the landscape into a sea of different colors. Tulip festivals are held throughout the country in spring. However, the most well-known tulip festival is organized in the Noordoostpolder, a province in the central Netherlands, each year. Held in the middle of the tulip fields, this flower festival runs from late April to early May. The Dutch people took their love of tulips abroad when they settled, and tulips and tulip festivals are now found in New York and Michigan, where the connection to their Dutch roots is still very strong.

    It's natural for all kids to worry at times, and because of personality differences, some may worry more than others. {#blank#}1{#/blank#} They typically worry about things like grades, tests, their changing bodies, fitting in with friends, the goal they missed at the soccer game, or whether they'll be bullied (欺负), or left out. Luckily, parents can help kids manage worry and deal with everyday problems.

    To help your kids manage what's worrying them:

    Find out what's on their minds.

    Be available and take an interest in what's happening at school, on the team, and with your kids' friends. {#blank#}2{#/blank#} As you listen to stories of the day's events, be sure to ask about what your kids think and feel about what happened. Sometimes just sharing the story with you can help lighten their load.

    {#blank#}3{#/blank#}

    Being interested in your child's concerns shows they're important to you, too, and helps kids feel supported and understood. Reassuring (令人安心的) comments can help—but usually only after you've heard your child out. Say that you understand your child's feelings and the problem.

    Guide kids to solutions.

    {#blank#}4{#/blank#} When your child tells you about a problem, offer to help come up with a solution together. If your son is worried about an upcoming math test, for example, offering to help him study will lessen his concern about it.

    Offer reassurance and comfort.

    Sometimes when kids are worried, what they need most is a parent's concern and comfort. {#blank#}5{#/blank#} It helps kids to know that, whatever happens, parents will be there with love and support.

    GLASGOW—the Chinese super star Lin Dan lost a thrilling men's singles final in straight games at the World Badminton Championships here on Sunday.

    The 33-year-old Lin,nicknamed Super Dan by his fans,was 9-13 behind in the first game as the 23-year-old Axelsen,who stands 1.95 meters,took command with powerful attacks.

    Lin,who won his fifth and last world title in 2013,managed to reach 13-13 with well-angled shots.They exchanged the lead several times before Lin took advantage at 20-19.Axelsen,the bronze medalist at last year's Rio Olympics,saved the game point and scored three points in a row for a 22-20 victory.The second game became a one-sided affair when Axelsen led all the way to win 21-16.Lin's expectation of winning a sixth world title was dashed by Denmark's Victor Axelsen.

    Axelsen became the third Dane to take world men's singles title following Peter Rasmussen in 1997 and Flemming Delfs in 1977.“It was a dream for me to win a world title,”Axelsen said.“I was shaking like a little child inside...Lin Dan is an idol for me.”

    Lin suffered his fourth defeat to Axelsen in their seven meetings,but he was satisfied with the result.“I am 34 at the end of this year and 35 next year.I think any player will find it very hard to play a world championships final at this age.I am satisfied with the result.”He added,“We both played well today.I should have killed off the first game when I led 20-19.But I made a mistake at the crucial time.If I won the first game,all the pressure would be at Victor's side.Unfortunately,I have to take all the pressure."

    Lin also dismissed any speculations about his retirement.“I will play in the Chinese National Games which kicks off tomorrow and then the Japan Open.I have been making very good preparations for this competition and I have showed that I am still strong enough physically.”

    Academic learning is usually in the spotlight at school, but teaching elementary-age students “soft” skills like self-control and how to get along with others might help to keep at-risk kids out of criminal trouble in the future.

    Once a program called Fast Track was started in the early 1990s for more than 7,600 children of 55 schools in America. They were identified by their teachers and parents to be at high risk for developing aggressive behavioral problems. The students were randomly divided into two groups; half took part in the intervention, which included a teacher-led curriculum, parent training groups, academic tutoring and lessons in self-control and social skills. The program, which lasted from first grade through 10th grade, reduced delinquency(少年犯罪), arrests and use of health and mental health services as the students aged through adolescence and young adulthood.

    In another latest study, by looking at the data from nearly 900 students in previous findings, researchers found that about a third of the influence on future crime outcomes was due to the social and self-regulation skills the students learned from ages 6 to 11.

    The academic skills, or hard skills like learning of physics, which were taught as part of Fast Track, turned out to have less of an influence on crime and delinquency rates than did the soft skills, which are associated with emotional(情绪的) intelligence. Soft skills might include teaching kids to work cooperatively in a group or teaching them how to think about the long-term consequences when they make a decision.

    Researchers drew the conclusion that these soft skills should be emphasized even more in our education system and in our system of socializing children. Parents should do all they can to promote these skills with their children as should education policymakers. To the extent we can improve those skills, we can improve outcomes in delinquency.

    A black hole is created when a large star burns out. Like our sun, stars are unbelievably hot furnaces(熔炉) that burn their own matter as fuel. When most of the fuel is used up, the star begins to die.

    The death of a star is not a quiet event. First there is a huge explosion. As its outer layer is blasted off into space, the dying star shines as brightly as a billion suns.

    After the explosion, gravity pulls in what's left of the star. As the outside of the star sinks toward the center, the star gets smaller and smaller. The material the star is made of becomes tightly packed together. A star is so solid that a teaspoon of matter from it weighs billion of pounds.

    The more the star shrinks(收缩), the stronger the gravity inside it becomes. Soon the star is very tiny, and the gravity pulling it in is unbelievably strong. In fact, the gravity is so strong that it even pulls light into the star! Since all the light is pulled in, none can go out. The star becomes black when there is no light. Then a black hole is born!

    That's what we know about black holes. What we don't know is this: What happens inside a black hole after the star has been squeezed into a tiny ball? Does it keep getting smaller and smaller forever? Such a possibility is hard to imagine.

    But if the black hole doesn't keep shrinking, what happens to it? Some scientists think black holes are like doorways to another world. They say that as the star disappears from our universe, it goes into another universe. In other words a black hole in our universe could turn into a "white hole" in a different universe. As the black hole swallows(吞噬) light, the white hole shines brightly--somewhere else. But where? A different place, perhaps, or a different time--many years in the past or future.

    Could you travel through a black hole? Right now, no. Nothing we know of could go into a black hole without being crushed(挤压). So far the time being, black hole must remain a mystery.

    Black holes are a mystery--but that hasn't stopped scientists from dreaming about them. One scientist suggested that in the future we might make use of the power of black holes. They would supply all of Earth's energy needs, with plenty to spare. Another scientist wondered if a black hole could some day be used to swallow earthly waste--a sort of huge waste disposal(处理) in the sky!

    There was a lot of news related to artificial intelligence, or AI, and machine learning. Among the stories were two dealing with direct competitions between humans and machines.

    In one competition, machines that used AI performed better than human beings in a high-level reading test. Two natural language processing tools beat human in the experiment. One of the tools was built by the American technology company Microsoft. The other was created by Chinese online seller Alibaba Group.

    In another competition, a computer took on humans in live, public debates.

    The event demonstrated how AI-powered computers are increasingly being developed to think ' and sound like humans. The organizer of the debates, U. S. technology company IBM, announced split results. It said a majority of those watching said they felt the machine had done more to improve their knowledge of the subject. But, the human got more praise for communicating their ideas.

    This year, we also explored the many ways AI and machine learning are now being used. For example, some U. S. judges use machine learning systems to help them decide when, and for how long, criminals should be jailed. The system uses computers to examine data from thousands of court cases.

    One fast-growing area of AI is facial recognition, which is increasingly being used for security purposes. Recently, Atlanta's Hartsfield-Jackson airport became the first in the U. S. to permit passengers to use facial recognition technology to get on flights. A Chinese company showed off an AI system it developed to recognize individuals by body shape and walking movements. The system is already being used by Chinese police in Beijing and Shanghai.

    In addition, machine learning was used during 2018 to predict results of the World Cup soccer competition. The technology also created artwork that sold for a large amount of money. And it is being used to help farmer save time and money, while reducing environment-harming chemicals. Other technology systems are being used to follow farm animals and wildlife to collect information on their activities.