We do not know when man first began to use salt, but we do know that it has been used in many different ways throughout history. Historical evidence shows, for example, that people who lived over 3,000 years ago ate salted fish. Thousands of years ago in Egypt, salt was used to preserve (保存) the dead.

    Stealing salt was considered a major crime (罪行) during some periods of history. In the eighteenth century, for example, if a person was caught stealing salt, he could be put in prison and his ears could be cut off.

    In the Roman Empire, one of the most important roads was the one that carried salt from the salt mines to Rome. Guards were stationed(安置) along the route to protect against salt thieves, and they received their pay in salt, thus bringing the English word, salary. Any guard who fell asleep while on duty was thought to be “not worth his salt”, and as a result he would get a little less salt on his next payday. The expression, “not worth his salt”, is still used today in English.

    In the modern world salt has many uses beyond the dining table. It is used in making glass and airplane parts, in the growing of crops, and in the killing of weeds (杂草). It is also used to make water soft, to melt (融化) ice on roads and highways, to make soap, and to fix colors in cloth.

    Salt can be got in various ways besides being taken from mines underground. Salt water from the ocean, salt water lakes or small seas can be used to make salt. Yet, no matter where it comes from, salt will continue to play an important role in the lives of people everywhere.

    The four theme parks below offer the most thrilling(刺激的)rides and attractions in the world.

Busch Gardens Williamsburg

    Located(坐落)in Virginia, USA, this theme paprk has some of the highest-rated thrill rides in the world. The park's famous roller coasters include Apollo's Chariot, Alpengeist, Griffon, the Loch Ness Monster and Verbolten. The park also has thrilling water rides, rides for kids, other rides, shows, tours, animal exhibits and more. Divided into nine areas representing European countries, the park has won an award for the quality of its food.

Everland

    One of the world's most popular theme parks, Everland is located in Yongin, Gyeonggi-do province, South Korea. The park has 40 thrill rides, including a world-famous wooden roller coaster, and many other attractions such as an hunting ride, a zoo, indoor and outdoor water parks, shows and more.

Blackpool Pleasure Beach

    This Lancashire amusement park is one of the most visited theme parks in the United Kingdom. Among the park's 125 rides and attractions are the tallest and faster roller coaster in the U. K., a classic wooden roller coaster, a steel tower ride, the biggest indoor dark ride in the world, a host of rides for kids and more.

PortAventura World

    Located on Spain's Costa Daurada, this park is divided into six themed areas. Five areas represent different locations including Polynesia, Mexico, the American West, China and the Mediterrancan. The sixth and newest area has a Sesame Street theme. The park has many rides and attractions suitable for visitors of all ages.

    NEW YORK—Australian mining enterpriser Clive Palmer on Tuesday unveiled(公布) blueprints (蓝本) for Titanic Ⅱ, a modern copy of the doomed ocean liner, although he didn't call the ship unsinkable any more.

    The ship will largely recreate the design and decoration of the fabled original, with some modifications to keep it in line with current safety rules and shipbuilding practices, and the addition of some modern comforts such as air conditioning, Palmer said at a press conference in New York.

    The three passenger classes, however, will be prevented from mingling(混杂), as in 1912, Palmer said. “I'm not too superstitious(迷信的). ”Palmer said when asked whether recreating a ship best-known for sinking was tempting fate.

    White Star Line, the operator of the original ship, had said the Titanic was designed to be unsinkable. About 1, 500 people died on Titanic's maiden voyage in 1912 from Southampton to New York after the ship collided with an iceberg in the North Atlantic.

    Palmer, who created the company Blue Star Line last year, refused to make a similar boast.

    “Anything will sink if you put a hole in it,”Palmer said. “I think it would be very cavalier(漫不经心的) to say it.”

    Unlike the original, TitanicⅡ will have more than enough space in its lifeboats for every person on board and will have additional escape staircases. Markku Kanerva, sales director at Deltamarin, the Finnish company designing the ship, said it would be “the safest cruise ship in the world”.

    Palmer refused to answer questions about the project's cost. Although the Titanic was the world's largest ship in her time, she would be smaller than many of today's modern cruise ships.

    “It's not about the money, ”Palmer said. “I've got enough money for it. I think that's all that matters.”

    Forbes estimated Palmer's net worth to be $795 million in 2012. He describes himself as a billionaire.

    TitanicⅡ will be built by Chinese state-owned CSC Jinling Shipyard, which has already built four ore carriers for Palmer's mining business, he said. The contract to build TitanicⅡ has not yet been signed, Palmer said.

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    Are you looking for a different place to visit this summer? Why not take a magical trip to an Earth-size planet beyond our solar system with NASA's Planet Travel Center?

    We live in a universe full of planets outside our solar system. Unluckily, even the nearest of those planets are light-years away, so sending spaceships and humans to these attracting worlds remains a distant dream. But on NASA's Planet Exploration website, you can start a journey on an imagined globe of a new world through 360-degree visualization（可视化）. As you land onto each globe's ground, you'll discover amazing views, like the blood-red sky of TRAPPIST-1d, or stand on a moon of the huge planet Kepler-16b, which appears larger than either of the planet's two suns. The view from each planet's ground is an artist's impression based on the limited information that is reachable; no real photos of these planets exist.

    The newest planet with such 360-degree visualization is Kepler-186f, an Earth-size planet rounding a star much cooler and redder than the Sun. “Kepler-186f is also so distant, and it is till now impossible to recognize their atmospheres—if they exist at all—or characterize their atmospheric qualities,” said Martin Still, scientist for NASA's newest space-based planet-hunting program, wondering people's reaction to their creation. “Though with such challenges unsettled, using the NASA visualization tool, you can see how the existence and disappearing of an atmosphere would change the view of the sky from the planet's ground.” Still added.

    Aaron, head of Planet Travel Center, points out that their present and future schedules of the globe visualization will find the nearest planets to our solar system and characterize their atmospheres, bridging the gap between our imagination and what's really out there. In the near future, all the 360-degree visualizations are viewable on desktop and mobile devices, like smartphones, allowing all readers a wonderful enjoyment from the possibilities of a new world.

    For centuries, mankind and dogs have suffered from a communication failure. We can tell dogs what we want them to do and sometimes they comply, but we've always struggled when it comes to understanding the true meaning of their barks and whimpers. There is exciting news now – a dog translator has been invented to help you communicate with your furry friend.

    Researchers at North Carolina State University have fashioned some kind of miracle dog translator body harness(束腰带). What's special about it is that it doesn't just rely on the dog's vocalizations to interpret what Fido is banging on about.

    Oh no – this miracle harness reads and interprets the ordinary dogs' body language as well, giving us a full two-way dog communication experience.

    Researcher David Roberts says: "Dogs communicate primarily through body language, and one of our challenges was to develop sensors that tell us about their behavior by observing their posture remotely."

    Sensors on the harness monitor the dog's heart rate and body temperature and software builds up a vocabulary, letting the human know what the dog is feeling.

    What would dogs say if they could talk to us? The human can even communicate back through the harness thanks to vibration motors, supposedly by tapping into the dog's senses so that it can understand what you're trying to say to it.

    The dog harness is designed for dogs involved in search and rescue and other front-line work, but it's got us dreaming of a beautiful future, one where humans and dogs can co-exist as equals, with the dog able to fully express itself at all times.

    More and more travellers in China nowadays prefer homestays rather than traditional hotels, as they seek private living experiences. The house-sharing model was first introduced by the website Couchsurfing, com in 2003. It is still the largest website for travellers to find accommodation(住宿) without much money to spend.

    Encouraged by her great experience of homestays in France, Maggita, 30, considered short-term hire as her first choice in her future trips. She later went back to her hometown Shanghai and ran a "shared accommodation" business.

    The short-term hire idea has been a win-win business model. For travellers, they can rent a special room at a reasonable price and also enjoy a firsthand experience of the local culture, compared with traditional hotels. For owners, they can gain much with daily rental. Now Maggita has quit her last job in an IT company and become a host of some 20 homestays, which enables her to earn a monthly income of around 40,000 —50,000 yuan.

    In recent years, China has seen many homestay booking websites such as Xiaozhu and Tujia. Chen Chi, the founder and CEO of Xiaozhu, said the model is to share rooms or apartments that are not in use with people who need them. Instead of the traditional view that Chinese people feel uncomfortable living with strangers, Chen found that a large number of travellers got along well with house owners.

    However, experts have pointed out a series of problems brought about by the fashion. Lacking supervision(监管) to those accommodation sharing websites, the service quality and accommodation safety cannot be guaranteed(保障).Experts suggest that the online websites should closely work together with communities and local police stations to improve the services.