You may think that light pollution isn't something extraordinarily important. You may believe that every other type of pollution has a larger impact on the environment that light pollution does. But light pollution is serious.

    Light pollution, or “sky glow”, is the glow you can see at night above cities and towns. Light pollution is a problem that has been accompanying man ever since he started his first fire some 15,000 years ago. Light pollution is the light that comes from streetlights, buildings, parking lots and any other source of light that is reflected or directed into the atmosphere.

    Urban light pollution means that one-fifth of the world's population can no longer see the Milky Way(银河) with the naked eye(肉眼). Many city kids, even if they did look through the orange smog above their heads, would probably see only a handful of stars. We have lost our view of the stars, and we have mucked up our  night-time environment as well. Astronomers are calling for the dark places on Earth to be preserved as national parks.

    Lots of people find the ever-brightening night annoying, and animals that are programmed to prefer the dark may avoid a brightened habitat. Sea turtles can get lost searching for a beach to lay eggs, and their hatchlings(孵化的幼仔)may confuse over-lit beachfront resorts(度假胜地) for the ocean horizon, wasting precious energy needed to find the sea and escape predators(食肉动物). Because their necks aren't yet long enough to see things far away, baby turtles rely on the mirror image of the moon to guide them to the sea, to begin their new life. A car may even hit a particular turtle, which was thinking the light from a nearby city was moonlight reflecting off the ocean waves. Birds that live in and around cities can die because of sky glow, too. The bright lights can blind them, leading to countless collisions with buildings and other tall structures.

    On an individual level, people can help reduce much sky glow by using lighting only when necessary. The stars above us are priceless heritage— for not only for astronomers but for all humans. More of our children should be able to look up at night and see the Milk Way.

    When other nine-year-old kids were playing games, she was working at a petrol station. When other teens were studying or going out, she struggled to find a place to sleep on the street. But she overcame these terrible setbacks to win a highly competitive scholarship and gain entry to Harvard University. And her amazing story has inspired a movie,“ Homeless to Harvard: The Liz Murray Story”, shown in late April.

    Liz Murray, a 22-year-old American girl, has been writing a real-life story of willpower and determination. Liz grew up in the shadow of two drug-addicted parents. There was never enough food or warm clothes in the house. Liz was the only member of the family who had a job. Her mother had AIDS and died when Liz was just 15 years old. The effect of that became a turning point in her life. Connecting the environment in which she had grown up with how her mother had died, she decided to do something about it.

    Liz went back to school. She threw herself into her studies, never telling her teachers that she was homeless. At night, she lived on the streets. “What drove me to live on had something to do with understanding, by understanding that there was a whole other way o f being. I had only experienced a small part of the society,” she wrote in her book Breaking Night.

    She admitted that she used envy to drive herself on. She used the benefits that come easily to others, such as a safe living environment, to encourage herself that “next to nothing could hold me down”. She finished high school in just two years and won a full scholarship to study at Harvard University. But Liz decided to leave her top university a couple of months earlier this year in order to take care of her father, who has also developed AIDS.“I love my parents so much. They are drug addicts. But I never forget that they love me all the time.”

    Liz wants moviegoers (who often see films) to come away with the idea that changing your life is “as simple as making a decision”.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    Since the 1970s, scientists have been searching for ways to link the brain with computers. Brain-computer interface (界面) (BCI) technology could help people with disabilities send commands to machines.

    Recently, two researchers, Jose Milan and Michele Tavella from the Federal Polytechnic School in Lausanne, Switzerland, demonstrated（展示）a small robotic wheelchair directed by a person's thoughts.

    In the laboratory, Tavella operated the wheelchair just by thinking about moving his left or right hand. He could even talk as he watched the vehicle and guided it with his thoughts.

    “Our brain has billions of nerve cells. These send signals through the spinal cord (脊髓) to the muscles to give us the ability to move. But spinal cord injuries or other conditions can prevent these weak electrical signals from reaching the muscles,” Tavella says.  “Our system allows disabled people to communicate with external world and also to control devices.”

    The researchers designed a special cap for the user. This head cover picks up the signals from the scalp(头皮) and sends them to a computer. The computer interprets the signals and commands the motorized wheelchair. The wheelchair also has two cameras that identify objects in its path. They help the computer react to commands from the brain.

    Prof. Milan, the team leader, says scientists keep improving the computer software that interprets brain signals and turns them into simple commands. “The practical possibilities that BCI technology offers to disabled people can be grouped in two categories: communication, and controlling devices. One example is this wheelchair.”

    He says his team has set two goals. One is testing with real patients, so as to prove that this is a technology they can benefit from. And the other is to guarantee that they can use the technology over long periods of time.

    Jack threw the papers on my desk. “Next time you want to change anything, ask me first,” he said. I had changed a long sentence and corrected its grammar — something I thought I was paid to do.

    Several days later, he made me angry again. I went to his office, prepared to lose my job if need be, but not before I let the man know how I felt. “What?” he said nervously.

    Suddenly I knew what I had to do. “Jack, the way you've been treating me is wrong. And it's wrong for me to allow it to continue,” I said. “I want to make you a promise. I will be a friend.” The next day I brought some cakes to Jack's office. Every time I saw Jack in the hall, I smiled at him. After all, that's what friends do.

    One year after our talk, I was told that I had breast cancer . When I was in hospital, my friends tried to find the right words to say, but no one could. The last day of my hospital stay, the door opened and Jack walked over to my bed. “Tulips (郁金香),” he placed some bulbs  beside me and said, “If you plant them when you get home, you'll be there to see them when they come up.” Tears filled my eyes.

    In a moment when I prayed for just the right words, a man with few words said the right thing. After all, that's what friends do. Now, I have seen those tulips push through the soil every spring for over ten years.

    I prefer Lynne Truss's phraseology: I am a grammar "sticker". And, like Truss—author of Eats, shoots & Leaves – I have a "zero tolerance" approach to grammar mistakes that make people look stupid.

    Now, Truss and I disagree on what it means to have "zero tolerance". She thinks that people who mix up basic grammar "deserve to be struck by lightning, hacked (砍) up on the spot and buried in an unmarked grave", while I just think they deserve to be passed over for a job—even if they are otherwise qualified for the position.

    Everyone who applies for a position at either of my companies, iFixit or Dozuki, takes a compulsory grammar test. If job hopefuls can't distinguish between "to" and "too", their applications go into the bin.

    Of course, we write for a living. iFixit.com is the world's largest online repair manual (指南), and Dozuki helps companies write their own technical documentation, like paperless work instructions and step-by-step user manuals. So, it makes sense that we've made a strong strike against grammar errors.

    But grammar is relevant for all companies. Yes, language is constantly changing, but that doesn't make grammar unimportant. Good grammar is credibility, especially on the Internet. And, for better or worse, people judge you if you can't tell the difference between "their" "there" and "they're".

    Good grammar makes good business sense—and not just when it comes to hiring writers. Writing isn't in the official job description of most people in our office. Still, we give our grammar test to everybody, including our salespeople, our operations staff, and our programmers.

    Grammar signifies more than just a person's ability to remember high school English. I've found that people who make fewer mistakes on a grammar test also make fewer mistakes when they are doing something completely unrelated to writing—like stocking shelves or labeling parts. It is the same with programmers. Applicants who don't think writing is important are likely to think lots of other things also aren't important.

    There were smiling children all the way. Clearly they knew at what time the train passed their homes and they made it their business to stand along the railway, wave to complete strangers and cheer them up as they rushed towards Penang. Often whole families stood outside their homes and waved and smiled as if those on the trains were their favorite relatives. This is the simple village people of Malaysia. I was moved.

    I had always traveled to Malaysia by plane or car, so this was the first time I was on a train. I did not particularly(特别) relish the long train journey and had brought along many magazines to read and reread. I looked about the train. There was not one familiar face. I sighed and sat down to read my Economics.

    It was not long before the train was across the Causeway and in Malaysia. Johor Bahru was just a city like Singapore, so I was tired of looking at the crowds of people as they hurried past. As we went beyond the city, I watched the straight rows of rubber trees and miles and miles of green. Then the first village came into sight. Immediately I came alive, I decided to wave back.

    From then on, my journey became interesting. I threw my magazines into the waste basket and decided to join in Malaysian life. Then everything came alive. The mountains seemed to speak to me. Even the trees were smiling. I stared at everything as if I was looking at it for the first time.

    The day passed fast and I even forgot to have my lunch until I felt hungry. I looked at my watch and was surprised that it was 3:00 pm. Soon the train pulled up at Butterworth. I looked at the people all round me. They all looked beautiful. When my uncle arrived with a smile, I threw my arms around him to give him a warm hug. I had never done this before. He seemed surprised and then his weather-beaten face warmed up with a huge smile. We walked arm in arm to his car.

    I looked forward to the return journey.