Six volunteers are about to find out what it would be like to live on Mars without ever leaving the Earth. Three men and three women will spend eight months living in a special place on the side of a volcano in Hawaii. They are part of an experiment that is designed to mimic（模仿）life on Mars. Their mission began on October 15, 2014. NASA says it could send astronauts to Mars as early as the 2030s. The mission would take more than two years, so NASA needs to know how people would react to living in a small group, isolated from the rest of the world, for such a long time. Some people may become depressed or bored living under those conditions. By studying people living in similar conditions here on Eares NASA hopes to learn how to choose the most suitable people for a space mission, and how to help them get along.

    They will live in a two-story building. The ground floor is about 86 square meters, roughly the size of a small two-bedroom apartment. It includes shared areas like kitchen, dining room, bathroom, laboratory and an exercise room. The upstairs is less than half the size of the downstairs. It contains another bathroom and six small bedrooms. The building is located in an abandoned quarry（采石场）about 2,400 meters up the side of Mauna Loa, the second biggest volcano in the world. It is constantly monitored for signs of volcanic activity. NASA chose the location because the appearance looks very similar to Mars.

    To make it more like being on Mars in the future, they are only able to communicate by email during the experiment. Meanwhile, there will be a 20-minute delay between the time when a message is sent and that when it is received. When they go outside, they will have to suit up in full spacesuits, just as if they were on Mars.

    The commander is Martha Lenio, a 34-year-old Canadian. During the mission, she will run experiments on growing food. The other members have backgrounds in physics and so on. None of them are astronauts.

    Chinese students aren't the only ones who have a sleep loss problem. In Australia, teenagers are also missing, on average, one hour's sleep every night during the school week.

    Organized activities and homework push bedtimes later, the first large-scale Australian study of children's sleeping habits has shown. Their sleep deprivation (剥夺) is enough to cause “serious drop-offs in school performance, attention and memory”, and governments should consider later or flexible school start times, said the study's leader, Tim Olds.

    His survey, of more than 4,000 children aged 9 to 18, found those who slept least did not watch more television but spent their time socializing (相处) with family or friends or listening to music.

    “Almost all children get up at 7 or 7:15 — they have to get to school on time,” said Olds. He favors a later start over an earlier finish because he believes organized sports and activities would still consume the latter end of the day.

    Olds' research also establishes lack of sleep as a cause of weight gain in children, and a possible source of future problems with depression, anxiety and increased susceptibility (易感性) to illness.

    It was already known that overweight children sleep less, but Professor Olds found sleep duration(时长) was strongly linked to weight across the full range of body sizes. The thinnest children sleep 20 minutes more than the obese. This showed being overweight had no specific effect on sleep patterns, and it was more likely that shorter sleep times stimulate (刺激) appetite and make kids hungry.

    The US National Sleep Foundation says teenagers aged 13 to 18 need eight to nine hours' sleep a night. Younger school-aged kids need 9 to 11 hours.

    On that basis, Professor Olds said, half of Australian children are under-sleeping on weekdays and a quarter on weekends.

阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项。

    The Gold Coast family holidays are always great fun whether you are from Australia or from abroad. There are beautiful beaches, adventure (冒险) parks, nature parks and so much more.

    There are so many sights to see here. It is a pity to drive in a car and you'll miss a great part of it. Australia is home to many animals and birds that can only be seen when moving slowly and going into the areas where they live.

    When you are on a bicycle, you have the advantage of being able to stop whenever you want to see an interesting animal or bird that you have never seen before. It is a quieter way of transportation as well, so you might even be able to take a picture. When you are on the beach, you can breathe that clean air and view the beauty of the water and sand. It is a totally different experience from passing it in a car.

    There are many choices of hiring (租用) a bicycle to experience the Gold Coast. There are stores that will fit a bike perfectly to your size. These bikes for both adults and children are in many kinds and colors to please any taste. If you have ever wanted to try a tandem bike (双人单车), now is your chance, because they have those too.

    A bicycle hire on Gold Coast is something that everyone should try at least once. This is a wonderful chance for anyone who likes to cycle and it is also a cheap way to travel with your family.

Hear the Wind Blow by Mary Downing Hahn

    On a cold, snowy night, 13-year-old Haswell Magruder makes an important decision. A wounded Confederate soldier appears at the family's farm, and Haswell convinces his mother to take the man in. Unfortunately, this sets off a horrific chain of events that leaves their house burned to the ground and their farm in ruins. With no home left, Haswell sets out in search of his older brother, a Confederate soldier.

    Ghosts of Greenglass House by Kate Milford

    Thirteen-year-old Milo is, once again, spending the winter holidays stuck in a house full of guests who are not what they seem. There are fresh clues to uncover as friends old and new join in his search for a mysterious map. The exciting ending to the beloved book is sure to thrill both fans and newcomers.

    Marge in Charge by Isla Fisher

    Jemima and Jake Button don't know what to make of their new babysitter, Marge. When she first arrives, she's dressed like a grandma and looks very serious. But as soon as Mommy and Dad are gone, Marge lets down her hair and the adventures begin. Jemima and Jake aren't supposed to shoot apple juice out of water guns, or throw impromptu (即兴的) concerts during music class—but with Marge here, everything's gone messy!

    Max Tilt: Fire the Depths by Peter Lerangis

    When 13 year old Max Tilt finds his great-great-grandfather Jules Verne's unfinished, unpublished manuscript (手稿), The Lost Treasures, he doesn't realize that he's found the answers to all his problems. He realizes that the book holds the key to something incredibly valuable. A treasure that can save his house — and maybe his entire family.

    A black hole is created when a large star burns out. Like our sun, stars are unbelievably hot furnaces(熔炉) that burn their own matter as fuel. When most of the fuel is used up, the star begins to die.

    The death of a star is not a quiet event. First there is a huge explosion. As its outer layer is blasted off into space, the dying star shines as brightly as a billion suns.

    After the explosion, gravity pulls in what's left of the star. As the outside of the star sinks toward the center, the star gets smaller and smaller. The material the star is made of becomes tightly packed together. A star is so solid that a teaspoon of matter from it weighs billion of pounds.

    The more the star shrinks(收缩), the stronger the gravity inside it becomes. Soon the star is very tiny, and the gravity pulling it in is unbelievably strong. In fact, the gravity is so strong that it even pulls light into the star! Since all the light is pulled in, none can go out. The star becomes black when there is no light. Then a black hole is born!

    That's what we know about black holes. What we don't know is this: What happens inside a black hole after the star has been squeezed into a tiny ball? Does it keep getting smaller and smaller forever? Such a possibility is hard to imagine.

    But if the black hole doesn't keep shrinking, what happens to it? Some scientists think black holes are like doorways to another world. They say that as the star disappears from our universe, it goes into another universe. In other words a black hole in our universe could turn into a "white hole" in a different universe. As the black hole swallows(吞噬) light, the white hole shines brightly--somewhere else. But where? A different place, perhaps, or a different time--many years in the past or future.

    Could you travel through a black hole? Right now, no. Nothing we know of could go into a black hole without being crushed(挤压). So far the time being, black hole must remain a mystery.

    Black holes are a mystery--but that hasn't stopped scientists from dreaming about them. One scientist suggested that in the future we might make use of the power of black holes. They would supply all of Earth's energy needs, with plenty to spare. Another scientist wondered if a black hole could some day be used to swallow earthly waste--a sort of huge waste disposal(处理) in the sky!

    Exercise could not only benefit your body, but also imp rove your memory, researchers found recently. In their paper published on Monday, researchers from the University of California, Irvine in the United States and the University of Tsukuba in Japan introduced their experiment and conclusion.

    Scientists invited 36 volunteers who were in their early 20s to do 10 minutes of light exercise before taking a memory test in which they were shown pictures like broccoli(西兰花)or picnic baskets and asked to recall them later. The same experiment was repeated with the same group of volunteers without exercising. "The memory task was really quite challenging ,said Michael Yassa, co-author of the study and a neuroscientist (神经科学家)at the University of California, Irvine. "We used very tricky similar items to see if they would remember whether it was this exact picnic basket versus (对抗)that picnic basket. "

    Researchers also scanned brains of some of the participants during the experiment. They found strengthened communication between regions involved in the storage and recollection of memories in brains of those who had exercised. This suggested that just 10 minutes of light exercise like walking, yoga or Tai Chi might increase memory power.

    As all the volunteers in the experiment were relatively young, researchers are still working to look at the effects of light exercise on older people. " Our future goal is to try to develop an exercise prescription (处方)that can be used by older adults who might have disabilities or mobility impairments, but can still adopt very simple exercise rules of life and be able to, perhaps, delay cognitive decline temporarily," said Yassa.