When I was 12, all I wanted was a signet (图章) ring. They were the "in" thing and it seemed every girl except me had one. On my 13th birthday, my Mum gave me a signet ring with my initials(姓名首字母) carved into it. I was in heaven.

    What made it even more special was that it was about the only thing that wasn't being "replaced". We'd been burnt out in fires that swept through our area earlier that year and had lost everything—so most of the " new" stuff (东西) we got was really just to replace what we'd lost. But not my ring. My ring was new.

    Then, only one month later, I lost it. I took it off before bed and it was missing in the morning. I was sad and searched everywhere for it. But it seemed to have disappeared. Eventually, I gave up and stopped looking for it. And two years later, we sold the house and moved away.

    Years passed, and a couple of moves later, I was visiting my parents' when Mum told me that she had something for me. It wasn't my birthday, nor was it Easter or Christmas or any other gift-giving occasion. Mum noticed my questioning look. " You'll recognize this one," she said, smiling.

    Then she handed me a small ring box. I took it from her and opened it to find my beautiful signet ring inside. The family who had bought our house 13 years earlier had recently decided to do some redecorations, which included replacing the carpets. When they pulled the carpet up in my old bedroom, they found the ring. As it had my initials carved into it, they realized who owned the ring. They'd had it professionally cleaned up by a jeweler before sending it to my mother. And it still fits me.

    Publishers of books for beginning readers are in the business of doing whatever they can to make children develop a love of reading. At times, that means they'll produce books that are more colorful and more packed with pictures. But it turns out that when it comes to learning to read books, more pictures aren't always better.

    In fact, simply having more than one picture on a page can negatively(消极地) affect the ability of preschoolers to learn words from that page, according to a new study by researchers at the University of Sussex. “Storybook reading is a great activity to help children increase their vocabularies,” writes co-author Zoe M. Flack in the University's School of Psychology blog.

    But the illustrations(插图) can affect how well children will learn new words. “For example,” Flack writes, “We know that children learn words better if illustrations are realistic.” Also, studies have shown that adding bells and whistles(哨声) to storybooks may negatively affect learning, according to Jessica S. Horst, Flack's co-author for the study. “We also know that children look within illustrations for the things they hear in the story, so if the story mentions a girl dropping an ice cream, children will look at the ice cream in the illustration.”

    With that in mind, Dr. Horst and Ms. Flack began to wonder what would happen when picture books show many illustrations on a page and how young children who haven't yet learned to read know which illustration to look at while listening to a story. To find out, they read storybooks that displayed either one or two illustrations per page to 36 three-year-old children. As it turns out, children who listened to stories with only one illustration at a time learned twice as many words as children who listened with two or more illustrations.

    Palaces are known for their beauty and splendor, but they offer little protection against attacks. It is easy to defend a large building, but usually these buildings are not designed with the comfort of a king in mind. When it comes to structures that are both beautiful and defensive, the European castle is a big success.

    Castles were originally built in England by the Normans in 1066. They built towers and walls to secure the land they had taken. These castles provided the Normans with a quiet and safe place. They also served as bases of operation for attacks. In this way castles served both defensive and offensive roles. Besides, castles served as offices for governors. Those that were socially beneath the governor would come to report affairs and express their respect. They would address problems, handle business, feast, and enjoy festivities in castles. So castles served as social centers as well.

    The first castles were made from earth and wood, and they were likely to suffer from attacks by fire. Then wooden castles were gradually replaced by stone, which greatly increased the strength of these towers and walls. However, attackers could throw flaming objects into castles through the windows or burn the wooden doors. This led to moving the windows and entrances off of the ground floor and up to the first floor to make them more difficult to access.

    During the Middle Ages, attacks increased in regularity, so castle defenses were updated. Arrow-slits were added. They were small holes in the castle, which allowed defenders to fire without being hurt. Towers were built from which defenders could provide fire on both sides. The towers were connected to the castle by wooden bridges, so that if one tower fell, the rest of the castle was still easy to defend. A lot of rings of castle walls were constructed, so that even if attackers went past one wall, they would be caught on a killing ground between inner and outer walls. All of these increased the defense of castles.

    The end of castles can be attributed to gunpowder. During the 15th century, artillery, a kind of large guns, became powerful enough to break through stone walls. This greatly made the role of castles less effective. Though castles no longer serve their original purposes, remaining castles receive millions of visitors each year who wish to experience the situations of ancient times.

    Nelson Mandela is respected and admired around the world. To South Africa he is a superstar. He is a hero who shocked the world by fighting for peace between races, even though he spent 27 years in the prison of the South Africa's white, racist regime(政权).

    Mandela, who won the nation's first all­race elections after the fall of apartheid (种族隔离) in 1994, retired in 1999. But even now, he is as popular as ever.

    His popularity has inspired an entire national industry. His portrait (肖像) has appeared at many places, including on some goods. His face has appeared on a South African coin, a district of a city was named in his honor and some business leaders hope to build a giant statue that looks like him—the Statue of Freedom in celebration of his birthday. It would stand taller than New York's Statue of Liberty.

    His popularity is similar to that of John F. Kennedy in the US or Winston Churchill in Britain, but few politicians today have achieved his level of admiration, said Tom Lodge, head of the Political Science Department of the University of the Witwatersrand.

    "Sometimes it isn't completely appreciated what a skilled performer Mandela has been throughout his political career. He's a very, very clever man."

    However, he is far from perfect.

    Most articles about his birthday, which appeared in every major South African newspaper on the day, briefly mentioned that Mandela did have shortcomings.

    Then they returned to their following praises.

    "Through the ages, the human race has had its icons(偶像)—men and women who rose above ordinary people to inspire their generations," The Mail and Guardian Weekly said, "In our generation, the god brought us Nelson Mandela."

    No one knows how much money Dr. Lyle Tullis gave away to students. I was his colleague for nearly a decade and I never stopped being amazed at his generosity. Our college has a program of providing cross-cultural experiences for students. Lots of students take advantage of summer experiences oversea. I discovered that no group left for overseas without some of its members receiving financial help from Dr. Tullis.

    It wasn't that he made a lot of money. For one thing, he taught in a church-run school. There, his salary (薪水) was half of what those people earned in a tax-supported school.

    Other colleagues occasionally complained about the low pay. Not Lyle Tullis. Occasionally some professors would leave our campus for a better-paid position. They told me they did so because, with better pay, they could provide for their families.

    The size of Lyle Tullis' paycheck never seemed to be the most important thing to him. I realized that one day when I was thanking him for helping a student, his eyes shone as he said to me, "I've got so much money that I don't know what to do with it. So, I just give it away."

    Most people wouldn't have thought that way. Dr. Tullis drove one of the oldest cars on campus. It was even older than almost any of the students' cars. His home, while comfortable, was not fancy at all. But Lyle Tullis lived with the feeling that he had so much money that he needed to give it away.

    He was one of the favorite on campus. Cynics (愤世嫉俗) might say he bought fame. But they would misunderstand. Lyle wanted to devote his life, all of it, to helping others.

Humans' voice sounds more pleasant than that of primates（灵长类动物）because we don't have vocal membranes （声带膜）, a new study suggests.

Humans have vocal cords（声带）, muscles in the top of the throat, which vibrate（振动）to produce sound. That unique part helps people control their voices well enough to produce sounds that form spoken language. However, unlike all the other studied primates, humans don't have vocal membranes.

To find out how vocal membranes affected spoken sounds, a team from Kyoto University took throats from monkeys that had died of natural causes and put the parts into devices, pushing air through the throats to see how the vocal cords and membranes would react. In the experiment, the researchers found that their vocal membranes and vocal cords vibrated together.

Researchers said these vocal membranes make it harder for other primates to control the voices they make. Without these membranes, humans vocal source is more balanced, allowing better voice control and production of long and balanced voices. A key thing that distinguishes human speech from animal sounds is our control over the sounds we make.

In humans, that sort of unpleasant voices can happen when we put extreme amounts of pressure on our voice, like baby crying and adult screaming. But those are rare cases. Researchers also said that our mouths and tongues could help control the voices. They are the basis of human languages.