People often ask which is the most difficult language to learn, and it is not easy to answer because there are many factors to take into consideration. Firstly, in a first language the differences are unimportant as people learn their mother tongue naturally, so the question of how hard a language is to learn is only relevant when learning a second language.

    A native speaker of Spanish, for example, will find Portuguese much easier to learn than a native speaker of Chinese, for example, because Portuguese is very similar to Spanish, while Chinese is very different, so first language can affect learning a second language. The greater the differences between the second language and our first, the harder it will be for most people to learn.

    Many people answer that Chinese is the hardest language to learn, possibly influenced by the thought of learning the Chinese writing system, and the pronunciation of Chinese does appear to be very difficult for many foreign learners. However, for Japanese speakers, who already use Chinese characters in their own language, learning writing will be less difficult than for speakers of languages using the Roman alphabet.

    Different cultures and individuals will find different languages more difficult. In the case of Hungarian for British learners, it is not a question of the writing system, which uses a similar alphabet, but the grammatical complexity, though native speakers may find it easier, struggling with languages that the British find relatively hard.

    No language is easy to learn well, though languages which are related to our first language are easier. Learning a completely different writing system is a huge challenge, but that does not necessarily make a language more difficult than another. In the end, it is impossible to say that one language that is the most difficult language in the world.

    Sitting is an art that isn't getting passed along. People these days feel as though they have to be doing something. If they are not working, they are jogging, or playing tennis or golf to guard against illnesses, or taking courses to improve their minds or bodies -- or they are parked in front of the TV. Sitting in front of the TV isn't sitting -- it's watching.

    People used to sit a whole lot. You would walk down the street or drive down the road, and there they would be, out on the doorsteps, sitting. You could go to the grocery to buy some garlic or some fruits and vegetables and sit on the bench out front m the summer or around the fire in the winter. You could go down to the store to buy an outer garment, an electric grill or anything else. There were sitting benches out in the town square. At the garage, there were straight-backed chairs. There among the oilcans and tires and spare parts, you could kick back and sit.

    Houses used to have sitting rooms, where the grown-ups would go after Sunday dinner. Mom and Dad, Grandpa and Aunt Ruby would gather round, sit and digest (消化) the fried chicken and talk about Aunt Ethel's illness, and how well the minister did today. They may just talk a load of garbage and even gesture with their hands when they become excited. Outside, the younger generation, the children would play on the ground, and the afternoon would pass by in a comfortable haze（ 悠闲的氛围).

    That sort of thing looks like doing nothing. A recharging battery (正充电的电池) doesn't look as if it's doing anything either. Sitting restores your soul. If you want to enjoy a truly full life, don't just do something--sit there.

    German engineers Gottlieb Daimler and Karl Benz built the first successful gasoline engines in 1885.After 1900, however, the United States became a leader in automobile production.

    The first cars were handmade and very expensive. Only people in rich cities could afford them. The first company to make gasoline cars in the U.S. was the Duryea Motor Wagon Company. Then, in 1901, Ransom E. Olds Began mass-producing his car, the Oldsmobile. In 1913Henry Ford made great strides in the mass production of cars by using an assembly line in his factory. Mass production meant that each car was less expensive to make. Now car ownership was affordable for the average person. By 1916there were more than one million cars in the United States.

    The automobile gave people the freedom to travel anywhere there were passable roads. Families that lived great distance apart could travel by automobile to visit each other. People could visit places they had never seen before.

    Before the mass production of cars, people lived close to work. Their means of transportation included walking, riding a bicycle, using a horse and carriage, or taking a train. The automobile gave people the ability to live farther away from work. The result was that gradually people moved out of the cities to the less crowded suburbs.

    The automobile industry created millions of jobs. The jobs were not just in the auto factories, where the cars were assembled. Workers were needed to make auto parts, run gas stations and repair shops, and work at new motels and restaurants that served people who traveled by car. Jobs became available at car rental companies. People were needed to build roads. These jobs and many others still exist because of the automobile.

    Tens of thousands of ancient pictures carved into the rocks at one of France's most important tourist sites are being gradually destroyed. Scientists and researchers fear that the 36,000 drawings on rocks in Mont Bego in the French Alps are being damaged so rapidly that they will not survive for future generations.

    The mountain, believed to have once been a site for prayer, is scattered (散布) with 4,000-year-old drawings cut into bare rock. They include pictures of cows with horns, cultivated fields and various gods and goddesses. But as the popularity of the site increases, the pictures are being ruined by thoughtless graffiti (涂鸦).

    Jean Clottes is the chairman of the International Committee on Rock Art. He says, "People think that because the pictures have been there so long they will always continue to be there. But if the damage continues at this rate there will be nothing left in 50 years."

    He describes seeing tourists stamping on the drawings, wearing away the rock and definition (清晰) of the artwork as they do so. Some visitors, he says, even cut off parts to take home as souvenirs. "When people think they can't take a good enough photograph, they rub the drawings to get a clearer picture," he said. "The drawings are polished by the weather, and if the sun is shining and the visitors can't see them properly they simply rub them to make them look fresher." Other researchers describe how people arrive carrying long sticks with sharp ends to scratch (刮) their own drawings, or even their names, in the rocks.

    But experts are divided over the best way to preserve the drawings. Henry de Lumley, director of the Museum of Natural History in Paris, believes that the only way to save the site is to turn the whole mountain into a "no-go" area, preventing the public from going there except on guided tours. Otherwise, he says, not only will the site be completely destroyed but important research work will be reduced.

    Clottes disagrees, "The measure suggested by Henry de Lumley is the most severe, and while it is the most effective, it is also certain to bring about protests from people who live there," he said. "The site was classified as a historic monument years ago by the Ministry of Culture, and we must do as much as possible to save what is there."

    David Lavergne, the regional architect, also wants to avoid closing the site. "Henry de Lumley's idea isn't ideal," he said. "Our department feels that the best solution is to let people look at the site, but because the area is very big it is difficult to prevent visitors from damaging it. I would prefer that everyone was able to look at it, but the main problem is money. We do not have the funds to employ the necessary number of guards. We may have to consider charging a fee. It doesn't seem to be possible to get the government support."

Preparing Cities for Robot Cars

    The possibility of self-driving robot cars has often seemed like a futurist's dream, years away from materializing in the real world. Well, the future is apparently now. The California Department of Motor Vehicles began giving permits in April for companies to test truly self-driving cars on public roads. The state also cleared the way for companies to sell or rent out self-driving cars, and for companies to operate driverless taxi services. California, it should be noted, isn't leading the way here. Companies have been testing their vehicles in cities across the country. It's hard to predict when driverless cars will be everywhere on our roads. But however long it takes, the technology has the potential to change our transportation systems and our cities, for better or for worse, depending on how the transformation is regulated.

    While much of the debate so far has been focused on the safety of driverless cars (and rightfully so), policymakers also should be talking about how self-driving vehicles can help reduce traffic jams, cut emissions (排放) and offer more convenient, affordable mobility options. The arrival of driverless vehicles is a chance to make sure that those vehicles are environmentally friendly and more shared.

    Do we want to copy—or even worsen—the traffic of today with driverless cars? Imagine a future where most adults own individual self-driving vehicles. They tolerate long, slow journeys to and from work on packed highways because they can work, entertain themselves or sleep on the ride, which encourages urban spread. They take their driverless car to an appointment and set the empty vehicle to circle the building to avoid paying for parking. Instead of walking a few blocks to pick up a child or the dry cleaning, they send the self-driving minibus. The convenience even leads fewer people to take public transport—an unwelcome side effect researchers have already found in ride-hailing (叫车) services.

    A study from the University of California at Davis suggested that replacing petrol-powered private cars worldwide with electric, self-driving and shared systems could reduce carbon emissions from transportation 80% and cut the cost of transportation infrastructure (基础设施) and operations 40% by 2050. Fewer emissions and cheaper travel sound pretty appealing. The first commercially available driverless cars will almost certainly be fielded by ride-hailing services, considering the cost of self-driving technology as well as liability and maintenance issues (责任与维护问题). But driverless car ownership could increase as the prices drop and more people become comfortable with the technology.

    Policymakers should start thinking now about how to make sure the appearance of driverless vehicles doesn't extend the worst aspects of the car-controlled transportation system we have today. The coming technological advancement presents a chance for cities and states to develop transportation systems designed to move more people, and more affordably. The car of the future is coming. We just have to plan for it.

    Good health is the most valuable thing a person can have, but one cannot take good health for granted. It is important to remember that the body needs proper care in order to be healthy. There are three things that a person can do to help stay in good shape: eat right food, get enough sleep, and exercise regularly.

    Proper nutrition (营养) is important for good health. Your body cannot work well unless it receives the proper kind of "fuel"(燃料).Don't eat too much food with lots of sugar and fat. Eat plenty of foods high in protein (蛋白质) ,like meat, fish, eggs and nuts. Vegetables and fruits are very important because they provide necessary vitamins (维他命) and minerals. However, don't overeat. It is not helpful to be overweight.

    Getting the proper amount of sleep is also important. If you don't get enough sleep, you feel tired and easily get angry. You have no energy. Over a long period of time a little amount of sleep may even result in a change of personality (人的个性). Be sure to allow yourself from seven to nine hours of sleep each night. If you do, your body will feel strong and refreshed, and your mind will be sharp.

    Finally, get plenty of exercise. Exercise firms the body, strengthens the muscles, and prevents you from gaining weight. It also improves your heart and lungs. If you follow a regular exercise program, you will probably increase your life-span (寿命). Any kind of exercise is good. Most sports are excellent for keeping the body in good shapes: basketball, swimming, bicycling, running and so on are good examples. Sports are not only good for your body, but they are enjoyable and interesting, too.

    If everybody, were to eat the right foods, get plenty of sleep and exercise regularly, the world would be a happier and healthier place. We would all live to be much older and wiser.