The first living creatures to travel in space were the dogs of the Soviet Unions space program.Beginning in 1951 dogs flew aboard sub－orbital flights to the height of 63 miles and higher.They helped to test the equipment that would later be used by humans.The first pair of dogs to fly，on July 22，1951，were named Tsygan and Dezik.

     Space dogs would make history on November 3，1957.On this date，just one month after the historic launch of the world's first artificial satellite，Sputnik，the Soviet Union shocked the world again by launching Sputnik 2.This satellite contained the first living creature to travel in space，a dog named Laika.Laika was to have orbited for a week or more until her food and oxygen ran out.In fact，Laika lasted only hours in orbit before over heating in her capsule(太空舱) took her life.

     That next step，occurred in August 1960，when the dogs Belka and Strelka made 18 orbits of earth and returned alive.Like Laika before them，they became distinguished ， featured in newspapers and magazines around the world.

     Six more orbital dog flights over the next eight months further tested the equipment necessary for humans to follow in the dogs' footsteps.That historic event happened on April 12，1961，when Yuri Gagarin became the first human to travel in space.

     The role of the space dogs had proven important in advancing the exploration of space.But，they would make one final flight.In 1966，traveling aboard the Cosmos 110 satellite，the dogs Ugolek and Veterok spent 22 days in orbit.Once again dogs led the way.Humans would not achieve a space flight that long for eight more years，in Skylab 2.

    The African elephant, which is the largest land animal remaining on earth, is of great importance to African ecosystem. Unlike other animals, the African elephant is to a great extent the builder of its environment. As a big plant-eater, it largely shapes the- forest-and-savanna (大草原) surroundings in which it lives, therefore setting the terms of existence for millions of other animals that live in its habitat.

    It is the elephant's great desire for food that makes it a disturber of the environment and an important builder of its habitat. In its continuous search for the 300 pounds of plants it must have every day, it kills small trees and under-bushes, and pulls branches off big trees. This results in numerous open spaces in both deep tropical forests and in the woodlands that cover part of the African savannas. In these open spaces are numerous plants in various stages of growth that attract a variety of other plant-eaters.

    Take the rain forests for example. In their natural state, the spreading branches overhead shut out sunlight and prevent the growth of plants on the forest floor. By pulling down trees and eating plants, elephants make open spaces, allowing new plants to grow on the forest floor. In such situations, the forests become suitable for large hoofed plant-eaters to move around and for small plant-eaters to get their food as well.

    What worries scientists now is that the African elephant has become an endangered species. If the elephant disappears, scientists say, many other animals will also disappear from vast areas of forest and savanna, greatly changing and worsening the whole ecosystem.

    Low-Cost Gifts for Mother's Day

    Gift No. 1

    Offer to be your mother's health friend. Promise to be there for any and all doctor's visits whether a disease or a regular medical check -up. Most mothers always say no need, another set of eyes and ears is always a good idea at a doctor's visit. The best part? This one is free.

    Gift No. 2

    Help your mother organize al1 of her medical records, which include the test results and medical information. Put them all in one place. Be sure to make a list of all of her medicines and what times she takes them. “Having all this information in one place could end up saving your mother's life,” Dr. Marie Savard said.

    Gift No. 3

    Enough sleep is connected to general health conditions. “Buy your mother cotton sheets and comfortable pillows to encourage better sleep.” Savard said. “We know that good sleep is very important to our health.”

    Gift No. 4

    Some gift companies such as Presents for Purpose allow you to pay it forward this Mother's Day by picking gifts in which 10 percent of the price you pay goes to a charity (慈善机构).Gift givers can choose from a wide variety of useful but inexpensive things many of which are “green”—and then choose a meaningful charity from a list. When your mother gets the gift, she will be told that she has helped the chosen charity.

    "Dreams may be more important than sleep. We all need to dream," some scientists say. Dreams take up about one quarter of our sleeping time. People have several dreams each night. Dreams are like short films. They are usually in colour. Some dreams are like old films. They come to us over and over again. That may be because the dreamer is worrying about something. Dreaming may be a way of trying to find an answer. Some people get new ideas about their work from dreams. They may have been thinking about their work all day. These thoughts can carry over into dreams.
    Sometimes we wake up with a good feeling from a dream. But often we can't remember the dream. Dreams can disappear quickly from memory. Too much dreaming can be harmful. The more we sleep, the longer we dream. The mind is hard at work when we dream. That is why we may have a long sleep and still wake up tired.

    Oct.15th was International White Cane Safety Day. You may have never heard of it, but it was a day to remember for Peng Baier, 17, of Nanjing Foreign Language School. After school that day, he visited his local Disabled Persons' Federation (残疾人联合会). He wanted to know about the sales and feedback (反馈) of his newly published book, How to Help a Disabled Person.

    Since he lives with his disabled grandparents, he understands that life can be hard for this group of people. Peng decided to write the book because he wanted to create a better life for disabled people in China.

    “Crossing the street is a big problem for them,” Peng said. “Speeding cars, people walking in a hurry, bikes on the sidewalk for the blind - accidents can happen everywhere. That's why we hardly ever see disabled people on the street, even though there are millions of disabled people in China.”

    Peng's book with pictures is easy to understand. It is a guide to the right and wrong ways to treat disabled people. The left-hand pages show the reader the right way; the right-hand pages point out mistakes that are commonly made.

    The teenager had 2,000 copies of his book printed. With the help of the Disabled Persons' Federation, he gave them to the disabled community.

    “The book is bilingual, so foreigners can also use it,” said Peng.

    Peng put great effort into the book. For example, he interviewed many disabled people to get first hand materials. He also studied textbooks from different schools for the disabled. Peng finally completed his handbook, but he still had the problem of getting it printed.

    How does a high school student raise money needed for that?

    With a smile, Peng said how he went about it. “I visited three local companies, dressed up in a suit and tie. I was lucky. The companies were warm-hearted and willing to give me a hand.”

    The surface of Venus（金星）has never seemed very hospitable. Temperatures change around 470℃（900℉）, the result of a runway greenhouse effect，and the pressure of its atmosphere, thick with carbon dioxide and sulfuric acid, is some 90 times that of Earth's. Lead（铅）would flow like water on Venus, and water cannot have existed in liquid form for perhaps a billion years.

    Now NASA'S Magellan spacecraft seems to have found one more horror in the nasty landscape: active volcanoes. Last week the space agency released the first detailed map of Venus and the most dramatic images ever made of its surface. The picture offer the best evidence to date that a planet once assumed dead is actually a lively pot of geological change.

    The most amazing image is of Venus's second tallest mountain, Maat Mons, which rises 8km（5 miles）. Most of the planet's many peaks, including 9.5-km-（6-mile-） high Maxwell Montes, look bright in the radar pictures Magellan takes from its orbit above the permanent could cover. That means they are strong reflectors of radar waves. But Maat Mons is dark; like the Stealth bomber, it absorbs much of the radar falling on it.

    This interesting fact, say project scientists, is a strong hint that the mountains has recently been covered with lava. Rock that sits on the surface of mountaintops appears to weather quickly in the hot，chemically reactive atmosphere, creating a soil that is rich in iron sulfide（硫化铁）• It is this mineral, the scientists believe, that can easily be seen on radar. If Maat Mons doesn't have any, it has probably been resurfaced, perhaps within the past few years.

    Such resurfacing has undoubtedly taken place in Venus lowlands: earlier images of the planet showed vast areas that are remarkably free of craters（火山坑）.That would be easy to explain on a Planet like Earth, where cratering from meteor strikes is erased by steady erosion. But while there is some evidence of wind erosion on Venus, the best explanation for the lack of cratering is periodic lava flow. Magellan has found direct evidence of such flows, including domelike upwellings and hardened streamed of rock trailing down the sides of Venusian peaks. There are also signs of other geologic activities, including dramatic faulting and several distinct incidents of mountain building. But the evidence can't indicate whether they really occurred millions of years ago. The case for active Venusian volcanoes is not yet proved, but Magellan, which is now well into its second complete survey of the planet's surface, may eventually settle the issue.