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    A buld-it-yourself solar still（蒸馏器） is one of the best ways to obtain drinking water in areas where the liquid is not readily available. Developed by two doctors in the U.S. Department of Agriculture, it's an excellent water collector. Unfortunately, you must carry the necessary equipment with you, since it's all but impossible to find natural substitutes. The only components required, though, are a 5'  5' sheet of clear or slightly milky plastic, six feet of plastic tube, and a container— perhaps just a drinking cup — to catch the water. These pieces can be folded into a neat little pack and fastened on your belt.

    To construct a working still, use a sharp stick or rock to dig a hole four feet across and three feet deep. Try to make the hole in a damp area to increase the water catcher's  productivity. Place your cup in the deepest part of the hole. Then lay the tube in place so that one end rests all the way in the cup and the rest of the line runs up — and out — the side of the hole.

    Next, cover the hole with the plastic sheet, securing the edges of the plastic with dirt and weighting the sheet's center down with a rock. The plastic should now form a cone(圆锥体) with 45-degree-angled sides. The low point of the sheet must be centered directly over, and no more than three inches above, the cup.

    The solar still works by creating a greenhouse under the plastic. Ground water evaporates (蒸发) and collects on the sheet until small drops of water form, run down the material and fall off into the cup. When the container is full, you can suck the refreshment out through the tube, and won't have to break down the still every time you need a drink.

    With the approval of the Singapore government, a company called nuTonomy has become the first-ever to test self-driving cars with the public. Interested people could sign up for a free trial run at no cost. When they received an invitation from the company, they could book a ride on the driverless taxi service from their smartphones.Not surprisingly,the rides proved very popular,with dozens of customers eagerly trying out the cars each day.

    Driverless cars are a great option for those who do not know how to drive and for those who do not enjoy driving.Some researchers even believe that such cars can make road travel safer by reducing human errors.But since driving requires many of our senses to be on alert（高度警觉）, replacing that by machines is easier said than done.

    The environment in which cars operate is constantly changing—from roads and pedestrians to co-travelers. A driverless car needs special equipment to analyze its surroundings. Then, it must translate that information into a practical route and safe travel. To be truly autonomous, a car has to do this independently without human input. Today, some cars have a certain degree of autonomous functions. But even the completely automated vehicles still require a driver to take back control under uncertain conditions.

    The island city-state is well known for excellent roads and drivers who obey the rules. This has made it ideal for real-world testing and feedback. The government has encouraged research in autonomous vehicles, since it can improve safety and potentially reduce the traffic burden as well.

The idea of being able to walk on water has long interested humans greatly. Sadly, biological facts prevent us ever accomplishing such a thing without artificial aid—we simply weigh too much, and all our mass pushes down through our relatively small feet, resulting in a lot of pressure that makes us sink.

    However, several types of animals can walk on water. One of the most interesting is the common basilisk Basilicus basilicus, a lizard (蜥蜴)native to Central and South America. It can run across water for a distance of several meters, avoiding getting wet by rapidly hitting the water's surface with its feet. The lizard will take as many as 20 steps per second to keep moving forward. For humans to do this, we，d need huge feet that we could bring up to our ears in order to create adequate w hitting.

    But fortunately there is an alternative : cornflour. By adding enough of this common thickening agent to water (and it does take a lot), you can create a “non-Newtonian” liquid that doesn't behave like normal water. Now, if the surface of the water is hit hard enough, particles(粒子）in the water group together for a moment to make the surface hard. Move quickly enough and put enough force into each step, and you really can walk across the surface of an adequately thick Liquid of cornflour.

    Fun though all this may sound, it's still rather messy and better read about in theory than carried out in practice. If you must do it, then keep the water wings handy in case you start to sink--and take a shower afterward!

    The first person in the world to receive two facial transplants says he is feeling well, three months after his latest groundbreaking operation.

    Jerame Hamon had his first transplanted face removed last year after signs of rejection following a treatment with an antibiotic (抗生素) during a cold.

    The 43 year old remained in a hospital in Paris without a face for two months while a compatible donor was sought.

    He said: “The first face I accepted immediately. This time it's the same.”

    Mr. Hamon suffers from neurofibromatosis (多发性神经纤维瘤), a genetic condition that spoiled his face severely.

    His first transplant, in 2010, was a success, but he caught a common cold in 2015 and was given antibiotics. The drug was incompatible with the immunosuppressive (免疫制疫的) treatment he was having to prevent a rejection of the transplanted material.

    The first signs of rejection came in 2016 and last November, the face, suffering from the death of most of cells, had to be removed.

    Mr. Hamon lived without a face in a room at Georges-Pompidou hospital in Paris without being able to see, speak or hear until January, when a face donor was found and the second transplant carried out.

    To avoid further rejection, Mr. Hamon—dubbed “the man with three faces” by French media ―had special treatment to clean the blood prior to the transplant.

    His new face remains smooth and motionless, and his skull, skin and features are yet to be fully matched. But he is positive about his recovery.

    “If I hadn't accepted this new face it would have been terrible. It's a question of identity… But here we are, it's good, it's me,” he told AFP news agency from the hospital, where he is still recovering.

    The hours-long operation was led by Prof Laurent Lantieri, a specialist in hand and face transplants who carried out Mr. Hamon's initial surgery eight years ago.

    “Today, we know that a double transplant is practicable, it's no longer in the field of research,” he told Le Parisien newspaper.

    Anaesthetist Bernard Cholley said: “Anyone who loses their face and then has to wait for a possible and imagined transplant for an unknown length of time—that's something that nobody has ever had to go through here.”

    “I'm amazed by the courage of a patient who has been able to get through such a different experience.”

    The first face transplant was carried out in 2005 in northern France. Since then, some 40 operations have been performed around the world.

    One of the United States' social problems is the breakdown of the two-parent family. Today, millions of American children grow up without fathers. Too often, these children lack the love and help they badly need and which they would ordinarily receive from not one but two parents. In the old days, American parents placed the needs of their children above their own. At present, however, nearly one half of all new marriages end in divorce(离婚), with often troubling results for their children. Worse, every year, thousands of teenage, unmarried Americans become mothers outside marriage. However, Chinese continue to value whole marriages. This is not to say that Chinese marriages are all perfect - they certainly are not, there are increasing more divorces in China - but the willingness of Chinese to set aside their own needs and stay together for the sake of the children is highly respected and worthy of study.

    Families are important to Americans. If one was to ask a group of Americans what is the dearest to them, the majority would say “family”. And yet, so many Americans spend much more time at work- that is, beyond the formal forty-hour work week - than they do with their own families. It seems to me that Chinese generally find a better balance between work and family needs than many Americans do. Average Chinese usually head home right after work，have meals together, and spend time with their family members. What's more, Chinese try to make more time for grandparents, uncles, aunts and cousins than many Americans; in many cases, multigenerational families live together. Of course, like many facts of Chinese society, this is all changing; increasing numbers of “New Chinese” are working longer hours and spending less time with their families than ever before. Still, while Americans do value their loved ones, I think we have something to learn from the Chinese about finding the proper balance between work and family.

    Many seniors feel pressured to go straight from high school to college, but Camden Olson, who graduated from the Latin School of Chicago in the US last year, didn't give in. She decided to spend a gap year-taking a year off before college-raising a guide dog for Guiding Eyes for the Blind in Maine. The non - profit provides trained guide dogs to blind and visually - impaired (视力障碍的) people. "This is something I've always wanted to do." Olson said.

    It is becoming more and more popular among American teenagers to have a gap year. Some students use the year off to figure out what they want to do: travel the world or save money for college.

    Olson is using her time to follow a passion she's had since 7th grade. For years, she kept an eye on guide dog services until she came across the opportunity at Guiding Eyes. With support from her friends, family and teachers, Olson went for it. Olson's volunteer work centers around Derby, a one-year-old black dog.

    "My job is to raise him to be well-mannered and socialized," she said. "Guide dogs can't be distracted. They go everywhere with their visually-impaired owner. They give a blind person a lot of support, too."

    Of course, there's an end in sight for Derby and Olson's close bond. When Derby celebrates his own graduation, Olson will have to say goodbye to him.

    "No doubt there will be tears, but, if he passes, I will be so happy for him to become a working dog," she said.

    While some do not agree that gap years are a good choice, Olson said she's seen major success. In fact, she'll be attending Princeton University soon and is thinking about majoring in biology.

    "I think I'm already so much more mature than I was," she said. "So many kids come back from gap years a lot more focused and prepared."