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。

    If cars had wings，they could fly and that just might happen，beginning in 2011.The company Terrafugia，based in Woburn，Massachusetts，says it plans to deliver its car­plane，the Transition，to customers by the end of 2011.

    “It's the next ‘wow' vehicle，” said Terrafugia vice president Richard Gersh.“Anybody can buy a Ferrari，but as we say，Ferraris don't fly.”

    The car­plane has wings that unfold for flying－a process the company says takes one minute－and fold back up for driving. A runway is still required to take off and land.

    The Transition is being marketed more as a plane that drives than a car that flies，although it is both. The company has been working with FAA to meet aircraft regulations，and with the National Highway Traffic Safety Administration to meet vehicle safety regulations.

    The company is aiming to sell the Transition to private pilots as a more convenient and cheaper way to fly. They say it saves you the trouble from trying to find another mode of transportation to get to and from airports：You drive the car to the airport and then you're good to go. When you land，you fold up the wings and hit the road. There are no expensive parking fees because you don't have to store it at an airport－you park it in the garage at home.

    The car­plane is designed to fly primarily under 10,000 feet. It has a maximum takeoff weight of 1,430 pounds，including fuel and passengers. Terrafugia says the Transition reduces the potential for an accident by allowing pilots to drive under the bad weather instead of flying into marginal(临界的) conditions.

    The Transition's price tag：$194,000.But there may be additional charges for options like a radio，a transponder or a GPS. Another option is a full­plane parachute.

    “If you get into a very awful situation，it is the necessary safety option，” Gersh said.

    So far，the company has more than 70 orders with deposits. “We're working very closely with them，but there are still some remaining steps，” Brown said.

    Far from the land of Antarctica (南极洲), a huge shelf of ice meets the ocean. At the underside of the shelf there lives a small fish, the Antarctic cod.

    For forty years scientists have been curious about that fish. How does it live where most fish would freeze to death? It must have some secret. The Antarctic is not a comfortable place to work and research has been slow. Now it seems we have an answer.

    Research was begun by cutting holes in the ice and catching the fish. Scientists studied the fish's blood and measured its freezing point.

The fish were taken from seawater that had a temperature of -1.88℃ and many tiny pieces of ice floating in it. The blood of the fish did not begin to freeze until its temperature was lowered to

-2.05℃. That small difference is enough for the fish to live at the freezing temperature of the ice-salt mixture.

    The scientists' next research job was clear: Find out what in the fish's blood kept it from freezing. Their search led to some really strange thing made up of a protein (蛋白质) never before seen in the blood of a fish. When it was removed, the blood froze at seawater temperature. When it was put back, the blood again had its antifreeze quality and a lowered freezing point.

    Study showed that it is an unusual kind of protein. It has many small sugar molecules（分子）held in special positions within each big protein molecule. Because of its sugar content, it is called a glycoprotein. So it has come to be called the antifreeze fish glycoprotein, or AFGP.

    Neuroscientists have explained the risky, aggressive or just plain baffling behavior of teenagers as the product of a brain that is somehow compromised. Groundbreaking research in the past 10 years, however, shows that this view is wrong. The teen brain is not defective. It is not a half-baked adult brain, either. It has been forged by evolution to function differently from that of a child or an adult.

    The most important of the teen brain's features is its ability to change in response to the environment by modifying the communication networks that connect brain regions. It allows teenagers to make enormous progress in thinking and socialization. But the change also makes them sensitive to dangerous behavior and serious mental disorders.

    The most recent studies indicate that the riskiest behaviors arise from a mismatch between the maturation of networks in the limbic system(边缘系统), which drives emotions at adolescence, and the maturation of networks in the prefrontal cortex（前额皮质）, which occurs later and promotes sound judgment and the control of impulses. Indeed, we now know that one's prefrontal cortex continues to change noticeably until his 20s. And yet adolescence seems to be starting earlier, extending the “mismatch years.”

    The plasticity of networks linking brain regions—and not the growth of those regions, as previously thought—is key to eventually behaving like an adult. Understanding that, and knowing that a widening gap between the development of emotional and judgment networks is happening in young people today, can help parents, teachers, counselors and teenagers themselves. People will better see that behavior such as risk-taking and turning away from parents and toward peers are not signs of cognitive or emotional problems. They are a natural result of brain development, a normal part of adolescents learning how to negotiate with a complex world.

    The same understanding can also help adults decide when to intervene. A 15-year-old girl's departure from her parents' tastes in clothing, music or politics may be a source of anxiety for Mom and Dad but does not indicate mental illness. A 16-year-old boy's tendency to skateboard without a helmet or to accept risky dares from friends is not unimportant but is more likely a sign of short-range thinking and peer pressure than a desire to hurt himself. Knowing more about the unique teen brain will help all of us learn how to separate unusual behavior that is age-appropriate from that which might indicate illness. Such awareness could help society reduce the rates of teen addiction, motor vehicle accidents and depression.

    As free as they make us, mobile phones still need to stay close to a power source. Soon that may change with "green" power.

    Three Chilean students got the idea for a plant-powered device(装置) to charge their cellphones, while sitting in their school's outdoor courtyard during a break from exams, with dead mobile phones. Then, one of them had an "aha" moment.

    “It occurred to Camila to say about plants,” said inventor Evelyn Aravena. “'Why don't you have a socket, if there are so many plants? 'After that, we thought, 'why don't they have a charging outlet? Because there are so many plants and living things that have the potential to produce energy, why not?'”

    Their invention—a small biological circuit called E-Kaia—uses the energy plants to produce during photosynthesis(光合作用). A plant uses only a small part of that energy and the rest goes into the soil, and that's where the E-Kaia collects it. The device plugs into the ground and then into your phone.

    "It's the most amazing project I've ever seen in my life, plain and simple. They brought this original model, and it worked — and that's when it all changed, at least from my personal point of view and I began to support them." said Mauricio Cifuentes.

    The device solved two problems for the engineering students — they needed an idea for a class project, and an outlet to plug in their phones.

    "Looking for a place to charge the notebook, which had no power, and the mobile phones, we weren't able to find anything because all the other students were in the same state of madness trying to find a place to charge their devices," said Aravena.

    But plants are everywhere, and the bio－circuit makes the best of their excess(过多的) power.

    The E-Kaia doesn't carry much charge but it's powerful enough to completely recharge a mobile phone in less than two hours.

    The student inventors have applied for patents on their technology, and expect the E-Kaia to go on sale in December 2016.