You have never seen him,but they're with you every time you fly.They record where you are going,how fast you're traveling and whether everything on your airplane is functioning normally.Their ability to withstand（经受得住）almost any disaster makes them seem like something out of a magic book.They're known as the black box.

    When planes fall from the sky,as a Yemeni airliner did on its way to Comoros Islands in the India ocean June 30,2009,the black box is the best bet for identifying what went wrong.So when a French submarine（潜水艇）detected the device's homing signal five days later,the discovery marked a huge step toward determining the cause of a tragedy in which 152 passengers were killed.

    In 1958,Australian scientist David Warren developed a flight-memory recorder that would track basic information like altitude and direction.That was the first mode for a black box,which became a requirement on all U.S.commercial flights by 1960.Early models often failed to withstand crashes,however,so in 1965 the device（装置）was completely redesigned and moved to the back of the plane-the area least affected bu impact-from its original position in the landing wells（起落架舱). The same year, the Federal Aviation Authority required that the boxes,which were never actually black,be painted orange or yellow to aid visibility.

    Modern airplanes have two black boxes: a voice recorder,which tracks pilots' conversations,and a flight-data recorder,which monitors fuel levels,engine noises and other operating functions that help investigators reconstruct the aircraft's final moments.Placed in an insulated ( 隔绝的) case and surrounded by a quarter-inch-thick panels of stainless steel,the boxes can withstand massive force and temperatures up to 2,000℉.When in deep water,they're also able to emit signals from depths of 20,000 ft.Experts believe the boxes from Air France Flight 447,which crashed near Brazil on June 1,2009,are in water nearly that deep,but statistics say they're still likely to turn up.In the approximately 20 deep-sea crashes over the past 30 years,only one plane's black boxes were never recovered.

    In England, people often talk about the weather because they can experience (经历) four seasons in one day. In the morning the weather is warm just like in spring. An hour later black clouds come and then it rains hard. The weather gets a little cold. In the late afternoon the sky will be sunny, the sun will begin to shine, and it will be summer at this time of a day.

    In England, people can also have summer in winter, or have winter in summer. So in winter they can swim sometimes, and in summer sometimes they should take warm clothes.

    When you go to England, you will see that some English people usually take an umbrella (伞)or a raincoat with them in the sunny morning, but you should not laugh at them.

    If you don't take an umbrella or a raincoat, you will regret (后悔) later in the day.

    Derek Rabclo is not the only surfer to conquer Hawaii' s famous Pipeline big wave break, but while all others use their sight to do it, this young professional surfer must rely only on his other senses. That's because he is completely blind.

    When Derek was born, over 24 years ago, he got his name from Derek Ho, the first Hawaiian surfing world champion. A surfing enthusiast himself, Emesto dreamed that his son would share the talent of his uncle, a professional surfer. Unfortunately, Derek was born completely blind, but this didn't slop his family from believing lhat he could do anything he wanted, even if that meant becoming a surfer.

    At age 2, Derek received a bodyboard and the beaches of Guarapari, Brazil, became his backyard. He was always comfortable in the water and surfing was in his blood, but he didn't actually try riding a wave until he turned 17, when his father bought him a surfboard. His father taught him the basics and encouraged him to keep practicing, but after successfully standing up on the surfboard, Derek knew he needed to become much better if he was going to achieve Emesto's dream and become a professional surfer. So he joined the Praia do Moroo surf school, where he studied under coach Fabio Maru.

    Standing up on a surfboard and conquering small waves is one thing, while gathering the courage to take on Hawaii's board-breaking Pipeline is another. But that's exactly what Derek Rabelo set out to do just months after learning how to surf. Everyone told him it was too dangerous, but he felt he could do it. And he did, earning the praise of famous professional surfers like Kelly Slater and Mick Fanning. Now 24, Rabelo has been surfing the Pipeline every winter since.

    With only about 1,000 pandas left in the world, China is desperately trying to clone the animal and save the endangered species. That's a move similar to what Texas A & M University researchers have been undertaking for the past five years in a project called "Noah's Ark".

    Noah's Ark is aimed at collecting eggs, embryos (胚胎), semen and DNA of endangered animals and storing them in liquid nitrogen. If certain species should become extinct, Dr. Duane Kraemer, a professor in Texas A & M's College of Veterinary Medicine, says there would be enough of the basic building blocks to reintroduce the species in the future.

    It is estimated that as many as 2,000 species of mammals, birds, reptiles will become extinct in over 100 years. The panda, native only to China, is in danger of becoming extinct in the next 25 years.

    This week, Chinese scientists said they grew an embryo by introducing cells from a dead female panda into the egg cells of a Japanese white rabbit. They are now trying to implant the embryo into a host animal. The entire procedure could take from three to five years to complete.

    "The nuclear transfer (核子移植) of one species to another is not easy, and the lack of available panda eggs could be a major problem," Kraemer believes. "They will probably have to do several hundred transfers to result in one pregnancy. It takes a long time and it's difficult, but this could be groundbreaking science if it works. They are certainly not putting any live pandas at risk, so it is worth the effort," adds Kraemer, who is one of the leaders of the Project at Texas A & M, the first-ever attempt at cloning a dog.

    "They are trying to do something that's never been done, and this is very similar to our work in Noah's Ark. We're both trying to save animals that face extinction. I certainly appreciate their effort and there's a lot we can learn from what they are attempting to do. It's a research that is very much needed."

    A new study, conducted by British company Mindlab International, has found that listening to music at work increases accuracy (精确) and speed, The Telegraph reported.

    Perhaps, some parents disagree with this idea, saying, "Switch off the music and concentrate!" Well, if that's the case with your parents, you might now be able to convince them that you have science on your side.

    The company gave 26 participants（参与者）a series of different tasks for five days in a row, including spell checking, mathematical word problems, data entry, and abstract reasoning. The participants completed these tasks while listening to music or no music at all.

    The results showed that while music was playing, 88% of participants produced their most accurate test results and 81% completed their fastest work. David Lewis, chairman of Mindlab International, told The Telegraph, "Music is a very powerful management tool if you want to increase not only the efficiency of your workforce but also their emotional state... they are going to become more positive about the work."

    However, you may have a list of your favorite songs, but not all kinds of music match all homework. For maths or other subjects involving numbers or attention to detail, you should listen to classical music, the study found. In the study, pop music enabled participants to complete their tasks 58% faster than when listening to no music at all. If you are reviewing your English writing, pop music is the best choice, as it is the best kind for spell checking. It cut mistakes by 14%, compared to listening to no music. After finishing your homework, do you often take time to check your answers? Maybe, some dance music is suitable for you.

    I have never been a fan of the phrase, "No pains, no gains." I prefer the alternative version, "No pains, no pains!" When it comes to exercise, for example, I learned years ago that pushing through pain was more likely to lay me up with an aching back than to leave me feeling strong and healthy.

    But there are times when stressful situations actually do lead to greater happiness. A new study published in the Journal of Happiness Studies found that people who pursue (追求) goals that are tough to achieve feel more stress in the moment, but greater happiness in the aftermath particularly if they feel connected to others along the way.

    The researchers concluded that happiness increases when people develop greater competence in something and greater competence only comes when people keep on working through the stress-inducing phase of trying, fighting, and trying again to learn and grow. If the psychological needs to be autonomous or self-directed, and to be connected to others are met, the momentary stresses will be less acute, and the resulting happiness will be more lasting.

    This idea reminds me of another often quoted phrase, which I have heard in reference to challenging tasks, such as exercise —"Fill-in-the-blank-stressful-task is the worst thing to do, but the greatest thing to have done." In other words, suffering from the stress of an exercise class that leaves us feeling sweat-drenched shouldn't lead us to walk away from exercising. And if we can pass those stressful moments with a friend, colleague or family member who is trustworthy and supportive, all will be better.

    As I travel my positive path, I'm certainly not seeking out stress. But life will offer me plenty of it, whether I ask for it or not. My task is to choose wisely when and how to face it head-on, knowing that happiness awaits on the other side.