For Suilasaikhan, a man living in the Inner Mongolia Autonomous Region(IMAR)(内蒙古自治区), life was hard years ago. When the wind blew, the sand made it almost impossible for him to see anything. He had to find his way back home by following the barking of dogs.

    Thankfully, things are much better today. About one third of the desert is now covered with trees, and sandstorms are less common. Ian Teh, who comes from Malaysia, came to China last year and was amazed to see people planting trees in the several deserts in northern China. "To be honest, it was hard to imagine it was ever a desert at all," he said.

    These are the results of Chinas years-long efforts to deal with desertification (沙漠化). In the 1950s, this widespread problem affected the life of about 400 million people in 18 provinces and autonomous regions in China. So China started several programs to deal with it. For example, the Three-North Shelter Forest Program, saw thousands of trees planted in northern China.

    In 1994, China joined the United Nations' convention (公约) against desertification and created the world's first law on sand prevention in 2001. With these efforts, the past five years have seen the area of desert in China decrease by 242,400 hectares.

    Desertification isn't the problem only in China. With china's success in dealing with desertification, the United Nations Environment Program (UNEP) believes the country is a good example for other countries to follow. "China is one of the most successful countries in greening the desert and has lessons to share with the world." UNEP Executive Director Erik Solheim told Xinhua.

    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.

    Philadelphia offers a ton of attractions that are suitable for people of every age and here are some family—friendly attractions.

    Spruce Street Harbor Park

    Spruce Street Harbor Park, one of the best urban beaches in America, is an outdoor heaven on the Delaware River waterfront. Visitors can relax in a hammock, play on the playgrounds, and play games like table tennis and giant chess. Don't miss out on the park at night, when colorful LED lights hanging from treetops make the entire area bright.

    Blue Cross River Rink

    Offering ice skating in the winter and roller skating in the summer, Blue Cross River Rink creates a fun, outdoor experience for the whole family. Visitors can play on the nine-hole mini-golf course during the summer, and enjoy eats and drinks from the on-site(现场的)bar and restaurant all year round.

    Sesame Place

    Big Bird, Elmo and the other stars of Sesame Street come out and play at Sesame Place, the only theme park in the nation starring the popular TV show's most lovable characters. A water park, interactive activities, parades, fireworks and shows add to the fun.

    Once Upon a Nation Storytelling Benches

    On summer days, uniformed and professional storytellers at 13 storytelling benches throughout Philadelphia's Historic District entertain visitors with true, free, three-to-five minute tales about the colonial(殖民的)era as part of Once Upon a Nation. Children can pick up a Story Flag at any storytelling bench, and then collect a star from every storyteller on their journeys. Flags with all the stars can get free rides on the Parx Liberty Carousel at Franklin Square.

    Youth volunteers from Beijing University visited Song tang Hospital, a care clinic for the aged and dying patients, during the second Global Youth Service Day on April 21．

    Thirty student volunteers from the university's School of International Studies sat at the beds of the patients in their specially decorated “care huts”. They talked with them and gave massages （按摩）to patients kept in their beds.

    I felt sorry that I could not offer more to these people than talking with them and trying to cheer them up, said Deng Yetao, 20, a third - year student. “But it occurred to me that they need more care and love than babies. They are afraid of the coming death. Their loneliness is worse than physical pains.”

    “Even though they are suffering a lot, the majority of the elderly people want to talk to us. Each of them has a lot of life experiences and philosophies to share. Instead of doing them a favor, I felt I was gaining a valuable lesson. Said Mao Xiaohua, another third - year student.

    Mao talked with two elderly patients for a whole afternoon. The fact that most of the patients in the 80 - room clinic are aged people with diseases which will lead to death soon made the volunteers' hearts heavy.

    Ninety - one percent of the patients will spend the last days of their lives in the clinic, according to a survey by the hospital.

    Daily visits and services by social workers and youth volunteers are a very important part of their programmer. A total of 330, 000 Beijing students from 119 universities and colleges have visited the hospital. Many continue to offer services in their spare time. Some of them volunteer to hold the hands of dying patients during the last minutes of their lives.

    Yin Hang, a student from Beijing Medical College, said he felt“ the glory of life” as he saw the fading smile on the face of the old man who passed into a deep unconsciousness（昏迷）while he was holding his hands.

    If you have the opportunity to visit some places in New Zealand, then the list below is our recommendation.

    Fiordland National Park

    This park is part of the South Westland World Heritage Area and is New Zealand's largest national park and one of the largest in the world. The scenery in Fiordland is nothing short of extremely beautiful, with steep mountains, wild waterfalls, and abundant rain forests. Being able to come back and forth in its deep bay attracts most of the visitors.

    The area has some of the world's greatest walks including the world famous Milford Track, which was described as the finest walk in the world in the early twentieth century.

    Abel Tasman National Park

    Abel Tasman may be New Zealand's smallest national park, but the attractions are huge. Located in one of New Zealand's sunniest spots, the area also has the best beaches in the country.

    The popular Abel Tasman Walk is a great way to see this park. It takes 3-5 days to complete. Sea taxis are also available and can drop you off at any number of beaches within the park.

    Rotorua

    Accessible from New Zealand's biggest city, Auckland, Rotorua is famous for its volcanic activities. Rotorua is also famous for its plentiful lakes which are great for swimming and fishing. The surrounding area contains plenty of native bushes and some famous walks.

    Rotorua is also the best area in the country to experience and learn about Maori culture.

    Mt Cook National Park

    Mt Cook as well as the surrounding area is an alpine(高山的) park within the World Heritage listed in South Westland. The biggest peaks in all of Australasia are here. The park doesn't contain many trees or plants due to the altitude. Walks range from a two­hour walk to difficult tracks suitable for experienced mountaineers only.

    A helicopter or plane ride gives visitors excellent views of the mountains with the option of landing at the top of Tasman Glacier, a true permanent snow­covered alpine environment.

    A new study suggests some language learning can take place during sleep. Researchers from Switzerland's University of Bern say they discovered people were able to learn new language words during deep levels of sleep.

    Much of the earlier research found that memories made when awake were strengthened during sleep. This supported the idea that information learned while awake is replayed and deeply embedded in the sleeping brain.

    The researchers theorized that, if replay during sleep improves the storage of learned information while awake, the processing and storage of new information should also be possible during sleep.

    They carried out experiments on a group of young German­speaking men and women, which centered on periods of deep sleep called "up­states". They identified these slow­wave peaks as the best moments for sleep­learning.

    The researchers observed individuals in a controlled environment during brief periods of sleep. Brain activity was recorded as pairs of words were played for the study subjects. One word in the pair was a real German word. The other was a made­up foreign word. For later identification purposes, the German words chosen were things clearly larger or smaller than a shoebox.

    Each word pair was played four times, with the order of the words changed each time. The word pairs were played at a rhythm that is similar to actual brain activity during deep sleep. The goal was to create a lasting memory link between the false word and the German word that individuals could identify while awake.

    When the subjects woke, they were presented with the false language words­both by sight and sound. They were then asked to guess whether the false word played during sleep represented an object smaller or larger than a shoebox. Results of the study found that a majority of subjects gave more correct answers about the sleep­learned words than would be expected if they had only guessed at random.

    The researchers said they measured increased signals affecting a part of the brain known as the hippocampus. This brain structure is very important for building relational memory during non­sleep periods. The researchers also said memory was best for word pairs presented during slow­wave peaks during sleep.

    The study suggests that memory formation in sleep appears to be caused by the same brain structures that support vocabulary learning while awake. The researchers say more studies are needed to support their findings. However, the experiments do provide new evidence that memories can be formed and vocabulary learning can take place in both conscious and unconscious states.