How is it that siblings (兄弟姐妹) can turn out so differently? One answer is that in fact each sibling grows up in a different family. The firstborn is, for a while, an only child, and therefore has a completely different experience of the parents than those born later. The next child is, for a while, the youngest, until the situation is changed by a new arrival. The mother and father themselves are changing and growing up too. One sibling might live in a stable and close family in the first few years; another might be raised in a family crisis, with a disappointed mother or an angry father.

    Sibling competition was identified as an important shaping force as early as in 1918. But more recently, researchers have found many ways in which brothers and sisters are a lasting force in each others' lives. Dr. Annette Henderson says firstborn children pick up vocabulary more quickly than their siblings. The reason for this might be that the later children aren't getting the same one-on-one time with parents. But that doesn't mean that the younger children have problems with language development. Later-borns don't enjoy that much talking time with parents, but instead they harvest lessons from bigger brothers and sisters, learning entire phrases and getting an understanding of social concepts such as the difference between “I” and “me”.

    A Cambridge University study of 140 children found that siblings created a rich world of play that helped them grow socially. Love-hate relationships were common among the children. Even those siblings who fought the most had just as much positive communication as the other sibling pairs.

    One way children seek more attention from parents is by making themselves different from their siblings, particularly if they are close in age. Researchers have found that the first two children in a family are typically more different from each other than the second and third. Girls with brothers show their differences to a maximum degree by being more feminine than girls with sisters. A 2003 research paper studied adolescents from 185 families over two years, finding that those who changed to make themselves different from their siblings were successful in increasing the amount of warmth they gained from their parents.

    The fence was long and high. He put the brush into the whitewash and moved it along the top of the fence. He repeated the operation. He felt he could not continue and sat down.

    He knew that his friends would arrive soon with all kinds of interesting plans for the day.

    They would walk past him and laugh. They would make jokes about his having to work on a beautiful summer Saturday. The thought burned him like fire.

    He put his hand into his pockets and took out all that he owned. Perhaps he could find some way to pay someone to do the whitewashing for him. But there was nothing of value in his pockets—nothing that could buy even half an hour of freedom. So he put the bits of toys back into his pockets and gave up the idea.

    At this dark and hopeless moment, a wonderful idea came to him. It filled his mind with a great, bright light. Calmly he picked up the brush and started again to whitewash.

    While Tom was working, Ben Rogers appeared. Ben was eating an apple as he walked along the street. As he walked along it, he was making noises like the sound of a riverboat. First he shouted loudly, like a boat captain. Then he said “Ding－Dong－Dong”,“Ding－Dong－Dong” again and again, like the bell of a riverboat. And he made other strange noises. When he came close to Tom, he stopped.

    Tom went on whitewashing. He did not look at Ben. Ben stared a moment and then said: “Hello! I'm going swimming, but you can't go, can you？”

    No answer. Tom moved his brush carefully along the fence and looked at the result with the eye of an artist. Ben came nearer. Tom's mouth watered for the apple, but he kept on working.

    Ben said, “Hello, old fellow, you've got to work, hey？”

    Tom turned suddenly and said, “Why, it's you, Ben! I wasn't noticing.”

     “Say—I'm going swimming. Don't you wish you could? But of course you'd rather work—wouldn't you? Of course you would.”

    Tom looked at the boy a bit, and said, “What do you call work？”

     “Why, isn't that work？”

    Tom went back to his whitewashing, and answered carelessly.

     “Well, maybe it is, and maybe it isn't. All I know is, it suits Tom Sawyer.”

     “Oh come, now, you don't mean to say that you like it？”

    The brush continued to move.

     “Like it? Well, I don't see why I shouldn't like it. Does a boy get a chance to whitewash a fence every day？”

    Ben stopped eating his apple. Tom moved his brush back and forth, stepped back to look at the result, added a touch here and there, and stepped back again. Ben watched every move and got more and more interested. Soon he said，“Say, Tom, let me whitewash a little.”

    Tom thought for a moment, and was about to agree, but he changed his mind.

     “No—no—it won't do, Ben. You see, Aunt Polly wants this fence to be perfect. It has got to be done very carefully. I don't think there is one boy in a thousand, maybe two thousand, that can do it well enough.”

     “No—is that so? Oh come, now—let me just try. Only just a little.”

“Ben, I'd like to, but if it isn't done right, I'm afraid Aunt Polly ”

     “Oh, I'll be careful. Now let me try. Say—I'll give you the core of my apple.”

     “Well, here—No, Ben, now don't. I'm afraid …”

     “I'll give you all of it.”

    Tom gave up the brush with unwillingness on his face, but joy in his heart. And while Ben worked at the fence in the hot sun, Tom sat under a tree, eating the apple, and planning how to get more help. There were enough boys. Each one came to laugh, but remained to whitewash. By the time Ben was tired, Tom sold the next chance to Billy for a kite; and when Billy was tired, Johnny bought it for a dead rat—and so on, hour after hour. And when the middle of the afternoon came, Tom had won many treasures.

    And he had not worked. He had had a nice idle time all the time, with plenty of company, and the fence had been whitewashed three times. If he hadn't run out of whitewash, Tom would have owned everything belonging to his friends.

    He had discovered a great law of human action, namely, that in order to make a man or a boy want a thing, it is only necessary to make the thing difficult to get.

    Colorado officials will stick to a plan to kill some mountain lions and bears to support the state's dropping mule deer (长耳鹿) population.

    Wednesday's vote permits organizations to kill up to 25 black bears and 15 mountain lions per year in the central and western parts of the state. The project will run for three years, to be followed by a six-year study of how deer populations respond to fewer predators(捕食者).

    The population of Colorado's mule deer has suffered a puzzling, years-long drop to about 450,000, which state officials said was about 110,000 fewer than there should be. A 2014 state study tied it to seven causes, including predators, whose number has greatly increased in recent years.

    Some experts, however, said the state should focus first on the human-led destruction(破坏) of mule deer habitat(栖息地). “The drop of the mule deer population is obviously not a simple problem with simple causes,” Brian Kurzel, director of the National Wildlife Federation, said. “By far, the greatest problem—the one that I think deserves the most attention in any science-based study—is habitat quantity and quality.”

    Kurzel pointed out that the U.S Bureau of Land Management recently agreed to create 15,000 new oil and gas wells somewhere in western Cororado, which was often called “the mule-deer factory”. There, the number of mule deer has fallen to about 30,000 from more than 100,000 in the early 1980s. Though state officials have known oil and gas development affects the population of mule deer, they didn't go against the plan.

    Other causes like building highways, population growth and human activities are also curbing the mule deer population, according to the study.

    State Parks and Wildlife officials don't necessarily disagree. They started a $4.5 million program as a way to gather research for later decisions.

    Mr. Guo is a teacher from Xi'an. He asked his students to hand in their homework through a QR code (二维码)."We spent an hour or two in class learning how to generate (使产生) the codes, and in the end everything gets easier." Said Guo, "When students finish the homework, they keep it on WeChat. Then, each student makes his own QR code and gives it to me. So I can check their work anywhere using my computer or telephone."

    The QR codes can be sent to Mr. Guo by email, QQ and WeChat. When Guo scans his students' QR codes, their homework appears on his phone. He finds that their homework becomes more creative, with many pictures, music and even videos.

    Guo's students like the new way and think it is interesting. "We are living in the information age. Many students like to work with computers, which makes learning more fun." said Tingting, a student of Guo's.

    "The paper is not easy to keep, but the code is easy to keep and share." Guo said, "It is worth trying to use new technology in education. Education itself is a kind of creation. I don't want my students to fall behind the times."

    However, some parents are worried. They are afraid that their children will spend too much time surfing the Internet and less time communicating with teachers. But in fact, it's unnecessary. Students still need to look up information in books and write it down when they do their homework. They only use the codes when they hand in their work, which doesn't take them too much time. Also for teachers, it allows them to check the students' work at any time. And it's also an easy way to share homework with other students.

    Charles Darwin lived an unusually quiet life. In 1842, Darwin and his wife Emma moved from London to Kent in southern England to have as little disturbance (烦扰) as possible. They already had two children then, and would go on to have eight more in the country.

    Darwin had very regular (有规律的) habits. He rose early and went for a walk. After breakfast he worked in his study until 9：30 am, his most productive time of the day, and then read his letters lying on the sofa before returning to work.

    At midday he would go for another walk with his dog, stopping at his greenhouse to inspect (查看) his experiments. Then he would go for another walk around an area of woodland. While walking on his "thinking path", Darwin would consider his unsolved scientific problems.

    After lunch he read the newspaper and wrote letters. His network of friends provided information from all corners of the world.

    The Darwins were not very strict parents and the children were always seen running wild. Their father worked patiently to a background of playful shouts and little footsteps walking past his study door.

After dinner Darwin played backgammon (a game for two people to play) with his wife. He once wrote, "Now the result with my wife in backgammon stands like this: she... has won only 2,490 games, while I have won, hurrah (a cheer of joy or victory), hurrah, 2,795 games!"

    Although he had poor health, Darwin continued to publish (出版)a lot of creative works until his final book in 1881. He died the following year, aged 73.

    Rather than a quiet space in the local churchyard, which he called "the sweetest place on Earth", Darwin was given a state funeral (国葬) in London's Westminster Abbey.

    News anchors(主播) must have been reluctant to read out the following news: Xin Xiaomeng began working as the world's first female artificial(人工的) intelligence news anchor at Xinhua News Agency on Sunday, three months after a male robot joined the profession.

    Unlike previous news robots though, Xin does not read news like a cold machine; she reads it almost like a human being. The muscles on her face stretch and relax — and her reactions change as she continues reading. That's why many news anchors were worried: Will AI replace us in the near future?

    To find the answer, we have to analyze the technologies that support Xin at her job. Three key technologies are used to support Xin. First, samples of human voices are collected and synthesized (合成). This is followed by the collection and synthesis of human muscle movement samples. And third the voices and movements are married in a way that when the AI news anchor reads, the micro- electric motors behind her face move to make her expressions seem more human.

    Yet we need a thorough knowledge of deep learning technology to make a robot imitate a person's voice. The developer needs to collect tens of thousands of pieces of pronunciations, input them into the machine and match them with the text for the AI to learn and read. The process for imitating facial movements is similar. The developer has to analyze the movements of the 53 muscles in the human face, make a model set from the collected data for the AI news anchor to learn, and imitate the movements of facial muscles via programs

    Both the technologies used to make Xin's performance impressive are mature. The real difficulty lies in the third — the technology to match the pronunciations with facial movements so that Xin's expressions vary according to the content of the news report. In fact, Xin's expressions don't always change according to the content. As a result, her expressions look anything but human. Actually, AI is still no match for human qualities.