A new study finds that young females in one group of African chimps(黑猩猩) use sticks as dolls more than their male peers (同龄) do, often treating pieces of wood like a mother chimp caring for a baby. In human cultures around the world, girls play with dolls and pretend that the toys are babies far more than boys do.

    Chimp observations, collected over 14 years of field work with the Kanyawara chimp community in Kibale National Park in Ugandan, provide the first evidence of a nonhuman animal in the wild that exhibits sex differences in how it plays. This finding supports an argument that biology as well as society underlies boys' and girls' different toy preferences.

    Stick play occurred most commonly between ages 3 and 9. Females spent a lot more time carrying sticks than males did. Young male chimps occasionally used sticks to mimic(模仿) childcare. "Far more often, they fought with sticks, an infrequent behavior among females," say Sonya Kahlenberg of Bates College in Lewiston, Maine, and Richard Wrangham of Harvard University.

    "Biological differences between the sexes make female chimps more receptive to stick-mothering than males," says Wrangham.

    Consistent with reported cultural traditions among adult chimps, Kanyawara youngsters learned from each other to play with sticks as if caring for babies. Stick play among young chimps showed no evidence of being directly influenced by older chimps. Child-bearing females never played with sticks and thus didn't model such behavior for younger chimps.

    Young females carried sticks for anywhere from a few minutes to several hours. They often rested in nests with their sticks, sometimes playing with them much as chimp mothers play with their babies though they didn't get any form of teaching from the adults.

    Christian Eijkman, a Dutch doctor, left the Netherlands for the island of Java. Many people on the island had a disease called beri-beri. He was going there to try and find a cure.

    At first, Eijkman thought some kind of germ (细菌) caused beri-beri. He raised some chickens. He didn't eat them, but made experiments on them. The local people were quite surprised at that. One day he noticed that his chickens became sick when they were fed the food most Javanese ate — refined white rice (精炼米). When he fed them with unrefined rice, also known as brown rice, they recovered. Eijkman realized that he had made an important discovery — that some things in food could prevent disease. These things were named vitamins. The Javanese were not getting enough vitamins because they had actually removed the part that contains vitamins. Later, other diseases were also found to be caused by the lack of vitamins in a person's food.

    Today many people know the importance of vitamins and they make sure they have enough vitamins from the food they eat. If they don't, they can also take vitamin pills.

    The Nazca Lines are a series of large ancient geoglyphs (地画) in the Nazca Desert, in southern Peru. It is ranging from geometric patterns to drawings of different animals and stylized human-like forms. The ancient lines can only be truly taken in from high in the air, leaving generations puzzled as to how these precise works could have been completed long before the documented invention of human flight.

    The Lines were first spotted when commercial airlines began flying across the Peruvian desert in the 1920,s. Who built them and what was their purpose? Are they roads, star pointers，maybe even a gigantic map? If the people who lived here 2,000 years ago had only a simple technology, how did they manage to construct such precise figures? Did they have a plan? These markings are like a vast puzzle.

    The Nazca Lines are the most outstanding group of geoglyphs in the world. There are also huge geoglyphs in Egypt, Malta，United States (Mississippi and California), Chile，Holivia and in other countries. But the Nazca geoglyphs, because of their numbers， characteristics, dimensions and cultural continuity as they were made and remade throughout a certain history period, form the most impressive archeological (考古学的) group.

    The Nazca plain is unique for its ability to preserve the markings upon it, due to the combination of the climate (one of the driest on Earth, with only twenty minutes of rainfall per year) and the flat, stony ground which minimizes the effect of the wind at ground level. With no dust or sand to cover the plain and little rain or wind to erode (腐蚀) it, lines drawn here tend to stay drawn. These factors, combined with the existence of lighter-colored subsoil beneath the desert surface, provide a vast writing pad that is suited to the artist who wants to leave his mark eternal.

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    Mrs Smith trembled(颤抖)with excitement when she was told her fortunes(命运). "Somebody is coming home to you, " Mrs Gray said slowly. "He's carrying a rifle(步枪)on his back and he's almost there."

    Mrs Smith felt as if she could hardly breathe. "And there he is!"Mrs Gray cried, pointing to the road. They all rushed to the door to look.

    A man in a blue coat, with a gun on his back, was walking down the road toward the Smith farm. His face was hidden by a large pack on his back.

    Laughing and crying, Mrs Smith grabbed(抓住)her hat and her children and ran out of Mrs Gray's house. She hurried down the road after him, calling his name and pulling her children along with her. But the soldier was too far away for her voice to reach him.

    When she got back to their farm, she saw the man standing by the fence. He was looking at the little house and the field of yellow wheat. The sun was almost touching the hills in the west. The cowbells rang softly as the animals moved toward the barn(畜棚).

    "How peaceful it all is, "Private Smith thought." How far away from the battles, the hospitals, the wounded and the dead. My little farm in Wisconsin. How could I have left it for those years of killing and suffering?"

    Mrs Smith hurried up to her husband. Her feet made no sound on the grass, but he turned suddenly to face her. For the rest of his life, he would never forget her face at that moment.

    "Emma!" he cried.

    The children stood back watching their mother kissing this strange man. He saw them, and kneeling down, he pulled from his pack three huge red apples. In a moment, all three children were in their father's arms. Together, the family entered the little unpainted farmhouse.

    Later that evening, after supper, Smith and his wife went outside. The moon was bright, above the eastern hills. Sweet, peaceful stars filled the sky as the night birds sang softly.

    His farm needed work. His children needed clothing. He was no longer young and strong. But he began to plan for next year. With the same courage he had faced the war, Private Smith faced his difficult future.

    When a terrible earthquake hit, many people were killed and many houses fell down. After the earthquake, all the newspapers reported many stories about some of the families who were in trouble.

    One Sunday, when I was reading a newspaper, a special picture touched me. It gave the clothing sizes of each family member. I thought that this would be a good chance to teach my children to help those who were less lucky than ourselves. I said to my seven-year-old twins, Brad and Brett, and three-year-old Meghan. "We have so much, and these poor people now have nothing. We'll share what we have with them."

    I filled a box with foods and clothes. While I was doing this, I encouraged the boys to choose their toys and donate some of their less favorite things. Meghan watched quietly as the boys took out their old toys and games and put them together. Then she walked away. A few minutes later she came back with Lucy, her much-loved doll. She put the doll on top of the other toys. "Oh, dear," I said. "You don't have to give Lucy. You love her so much." Meghan said, "Lucy makes me happy, Mommy. Maybe she'll make another little girl happy, too."

    I looked at Meghan for a long moment. She taught me a lesson. It's easy to give something that we don't want any more, but harder to give what we cherish (珍爱), isn't it?