阅读理解。阅读下列短文, 从给的四个选项 (A、B、C和D) 中, 选出最佳选项。

     Isaac Stern was  more  than a great violin player.He was one of the most honored musicians in the world.He was an international  cultural ambassador.He was a major supporter of the arts in America and in other countries.He was a teacher and activist.

     Isaac Stern was born in 1920 in what is now Ukraine.His parents moved  to  San Francisco，California the following year.His mother began teaching Isaac the piano when he was six. He began taking violin lessons after hearing a friend play the instrument.Later，he began studying music at the San Francisco Conservatory(音乐学院)．He progressed quickly.When he was 16，he played with the San Francisco Symphony Orchestra.The next year，he performed in New York City and was praised by music critics.

     During World War II ，Mr.Stern played for thousands of American soldiers.It was the first time many of them had heard classical music.After the war，he was the first American violinist to perform in a concert in the Soviet union.He also supported young musicians and cultural organizations in Israel.

    In 1979，Isaac Stern visited China.He met with Chinese musicians and students.He taught them about classical Western music.His visit was made into a film，which is called From Mao to Mozart：Isaac Stern in China.It won an Academy Award for best documentary film.

     In 1984，Isaac Stern received the Kennedy Center Honors Award for his gifts to American culture through music.He expressed his thoughts about the part that music plays in life.He said he believed that music makes life better for everyone，especially children.

     Mr.Stern supported and guided younger classical musicians.They include violinists Itzhak Perlman and Pinchas Zukerman，cellist Yo­Yo Ma，and pianist Yefim Bronfman.

     Isaac Stern died in 2001 at the age of 81.He was a major influence on music in the 20th century.He leaves the world richer with his many recordings.

Mark Twain's First Money

      Mark Twain was asked one day if he could remember the first money he ever earned. He thought a long time and then said, "Yes, it was at school. I can remember everything about it. School boys in those days did not take good care of their chairs and desks. There was a rule in our school that if anyone damaged his desk or chair, he would have to pay five dollars or the teacher would beat him in front of the whole school."

    "One day I damaged my desk in some way, I had to pay five dollars or be beaten before the whole school. My father said it would be too bad to have our family disgraced in front of the whole school. He agreed to give me five dollars to hand over the teacher. But before he gave me the money, he took me upstairs and gave me a beating."

    "But as I had one beating and I decided I would take another beating at school and keep the five dollars. So that's what I did. That was the first money I ever earned."

Why Mars (火星) is New Settlement

    Is it possible to live on other planets? The United States government is taking a serious look at the moon and Mars as potential places for future human settlement. The moon could serve as a training ground for later journeys to Mars. Currently, with Mars becoming the eventual long-term goal, serious questions exist as to whether the dangers of the settlement on the moon are too extreme and unnecessary.

    One major reason the settlement on the moon is too dangerous is the difference between the atmosphere environment of the moon and Mars. Atmosphere is important because it protects humans and all other life from a continuous attack of radiation (辐射) caused by sources such as the sun. This radiation is especially dangerous to humans because it increases the risk of cancer and can negatively change DNA. The fact that the moon has no atmosphere can cause great harm to human beings. Although Mars' atmosphere is significantly thinner than Earth's, at least it has one and would create some sort of protective barrier for humans.

    Another important characteristic necessary for human settlement is natural resources like water, of which the moon is believed to have none. Mars, however, contains vast quantities of water ice, dry ice, and also snow. There is also sufficient evidence that water once existed at the surface of Mars and might return in the future if the planet warms. With increased technologies, the potential for settlers to remain on Mars by being increasingly self-sufficient makes Mars a much more attractive goal as the space settlement than the moon.

    Future settlers will not only benefit from potential water on Mars; the planet is also rich in other natural resources such as oxygen, hydrogen, and minerals, which can be well used in productive ways.  For example, hydrogen can be used as fuel, and it can be combined with nitrogen (氮气) to form new materials necessary for human settlement. Due to these advantages,

    Mars would be a more successful planet for exploration and settlement because it contains the basic resources necessary for humans to survive.

    Since the environment of Mars is more similar to that of Earth and it contains resources necessary to  help  life  exist,  it should  be  the  only option for any kind of long-term human settlement. The settlement on Mars would not only be a milestone in space but also an excellent chance for mankind to improve itself from past adventures on Earth and preserve and make the best use of the natural resources Mars has to offer.

    Sitting has been called the new smoking for its supposed Public health risks, especially for people with sitting down office jobs. Over the past 15 years or so sitting has been connected with heart disease and diabetes (糖尿病). But is sitting really that risky?

    In our latest study we examined if not only the total amount of sitting, but different types of sitting, were connected with developing type 2 diabetes. We wanted to see if there was any difference among sitting watching TV, sitting at work, or sitting at home but not watching TV.

    We studied sitting habits of 4. 811 middle-aged people, who didn't have diabetes or heart problems at the start of the study. Over the next 13 years, 402 people developed diabetes. Once we considered obesity (AE RF), Physical activity, and other things that may develop type 2 diabetes, neither total sitting time, sitting at work nor sitting at home but not watching TV were connected with developing diabetes. We found only a weak connection with the time spent sitting watching TV and an increased risk of developing diabetes.

    This is different from the results of five older TV studies that showed a stronger connection. But hardly any of the included studies mentioned obesity, a major cause of diabetes.

    For people who are physically inactive, though, the story's different. Two recent studies show the total time spent sitting a day is connected with developing diabetes, but only in people who are physically inactive or both physically inactive and obese.

    That's not the whole story. At least two things determine if sitting is a risk factor in its own right: the type and situation of sitting.

    For example, sitting down at work isn't strongly connected with long-term health risks, Perhaps that's because higher position jobs needs more sitting, and higher socioeconomic (社会经济) position is connected with a lower risk of disease. It's a different case for sitting watching TV, the type of sitting most possibly connected with long-term health risks. People who watch a lot of TV tend to (a) be of lower socioeconomic positions, unemployed, have poorer mental (精神上的) health, eat unhealthy foods and face more unhealthy food advertising.

The Young Scholars Program

    The University of Maryland's Young Scholars Program is a perfect summer camp for academically talented teenagers who want to earn college credits, pursue academic interests or discover college life at the University of Maryland. The program is challenging and rewarding. Students have the opportunity to show that they can be successful in a university environment.

    The Activities

    During three weeks of exploration, teens preview the university experience, study with students who share similar interests and communicate with the best teachers of the University of Maryland in a dynamic and challenging classroom environment. Students can have trips to nearby Washington, DC and enjoy movie nights and activities at the student union. Workshops and seminars featuring speakers in academic fields further enrich the learning experience.

    The Courses

    The Young Scholars Program offers college courses that are at the cutting edge of theory, thought and technology. Classes generally meet every day from Monday to Friday. The program is a great introduction to the University of Maryland, Participants can benefit from the University of Maryland's vast resources, including libraries, computers and instructional labs.

    The Rewards

    Upon program completion, teens will go home with better preparations for the college experience—both academically and socially. In addition, students earn three college credits that post to the University of Maryland transcript (成绩单).

    The Application

    The application process includes submission of the application, high school transcript and a letter of recommendation.

    Ages: 14-18

    Mailing address: The University of Maryland College Park

    For more information, call 3014057762.

    Thirteen vehicles lined up last March to race across the Mojave Desert, seeking a million in prize money. To win, they had to finish the 142-mile race in less than 10 hours. Teams and watchers knew there might be no winner at all, because these vehicles were missing a key part－drivers.

    DARPA, the Defense Advanced Research Projects Agency, organized the race as part of a push to develop robotic vehicles for future battlefields. But the Grand Challenge, as it was called, just proved how difficult it is to get a car to speed across an unfamiliar desert without human guidance. One had its brake lock up in the starting area. Another began by throwing itself onto a wall. Another got tied up by bushes near the road after 1.9 miles.

    One turned upside down. One took off in entirely the wrong direction and had to be disabled by remote control. One went a little more than a mile and rushed into a fence; another managed to go for six miles but stuck on a rock. The "winner," if there was any, reached 7.8 miles before it ran into a long, narrow hole, and the front wheels caught on fire.

    "You get a lot of respect for natural abilities of the living things," says Reinhold Behringer, who helped design two of the car-size vehicles for a company called Sci-Autonics. "Even ants (蚂蚁) can do all these tasks effortlessly. It's very hard for us to put these abilities into our machines."

    The robotic vehicles, though with necessary modern equipment such as advanced computers and GPS guidance, had trouble figuring out fast enough the blocks ahead that a two-year-old human recognizes immediately. Sure, that very young child, who has just only learned to walk, may not think to wipe apple juice off her face, but she already knows that when there's a cookie in the kitchen she has to climb up the table, and that when she gets to the cookie it will taste good. She is more advanced, even months old, than any machine humans have designed.