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.

    All over the world people enjoy sports, Sports help to keep people healthy and happy, and to live longer.

    Many people like to watch others play games. They buy tickets or turn on their TVs to watch the games. Often they get very excited when "their" player or team wins.

    Some sports are so interesting that people everywhere go in for(参加) them. Football, for example, has spread(展开)around the world. Swimming is popular in all countries near the sea or in those with many rivers. What fun it is to jump into a pool or lake, whether in China, Egypt or Italy! And think of people in cold countries. Think how many love to skate or ski (滑雪) in Japan, Norway or Canada.

    Some sports or games go back thousands of years, like running or jumping. Chinese wushu, for example, has a very long history. But basketball and volleyball are rather new. Neither one is a hundred years old yet. People are inventing new sports or games all the time. Water-skiing is one of the newest in the family of sports.

    People from different countries may not be able to understand each other, but after a game together they often become good friends. Sports help to train(培养,训练) a person's character(性格,品格). One learns to fight hard but fight fair, to win without pride and to lose with grace(胜不骄，败不馁).

    A European Union program is letting blind people experience famous paintings for the first time. It uses three dimensional (3-D) printing to re-create famous paintings so that they can be touched.

    One painting printed with the new technology is Gustav Klimt's "The Kiss." It is a popular attraction at the Belvedere Museum in Vienna, Austria. The painting shows a man and a woman standing in a field filled with flowers. They are wearing gold robes and have their arms around each other. The man leans down to kiss the woman.

Klimt finished the painting in 1908. Until now, people who have trouble seeing can not enjoy the artwork. But thanks to the reproduction (复制品) they can touch the piece and feel the ridges (隆起) and depressions (凹地). Andreas Reichinger started making 3-D versions of artwork in 2010. He said this reproduction was his most difficult project because the couple's robes are so detailed (精细的).

    Dominika Raditsch is a blind museum visitor. She touched the reproduction. As she moved her hands around it, she said, "Exactly, can you see these? There are so many details." Raditsch said she can imagine what the original painting looks like when she touches the reproduction. "It's somehow round. You can feel it. It comes with it. And in many places it's so smooth. And then I think to myself: it probably shines too!" Raditsch said.

    The Belvedere is not the only museum to have 3-D versions of its artwork. Some of the pieces at the Prado, in Madrid, Spain, have reproductions that can be touched. But the piece in Vienna has one special part: it is made with widely available 3-D printing technology. That means one day, blind art fans anywhere in the world could download the source files and print the reproductions themselves.

    A study examining the children of people evacuated(撤离) during the WWII showed the daughters of female evacuees were up to four times more likely to suffer from serious mental health conditions compared to those whose parents stayed at home.

    In the largest enquiry ever of its kind, researchers examined the health records of 3000 children of Finnish people evacuated to Sweden during the 1941-1945 conflict with Soviet Russia. The evacuees, many of whom were at a pre-school age, were placed with foster families in Sweden and were forced to learn Swedish, later returning to Finland. The study found that the female children of these girls had an increased risk of being hospitalized for conditions such as depression. However, this was not the case with children of boys evacuated during the war.

    The study could not determine why. One possibility is that the stress of the evacuees' experience affected their psychological development in ways that influenced their parenting style. Another possibility is that the evacuees' experience resulted in epigenetic changes—changed in the way genes are expressed. For example, the researchers mentioned an earlier finding that Holocaust survivors have higher levels of methyl groups bound to the FKBP5 gene and have passed his change on to their children. This higher level of methyl groups appears to change the production of cortisol, a hormone(荷尔蒙) that controls the stress response.

    "The Finnish evacuation was intended to protect children from the harm associated with the country's wars with the Soviet Union", said study co-author Dr Torsten Santavirta, from Uppsala University.

    "Our observation of the long-term psychiatric(精神病的) risk that reached into the next generation is concerning and stresses the need to weigh benefits as well as potential risks when designing policies for child protection".

    Shark attacks not only disturb beach activities, but can affect associated tourist industries. Shark nets are a common solution to preventing shark attacks on beaches, but they cause dangers to sea ecosystems.

    Seeking a cost-effective way to monitor beach safety over large areas, we have developed a system called Shark Spotter. It combines artificial intelligence (AI), computing power, and drone (无人机) technology to identify and warn lifesavers to sharks near swimmers. The project is a cooperation between the University of Technology Sydney and The Ripper Group, which is pioneering the use of drones—called "Westpac Little Ripper Lifesavers"—in the search and rescue movement in Australia.

    SharkSpotter can detect sharks and other potential threats using real-time aerial imagery. The system analyses video from a camera attached to a drone to monitor beaches for sharks, send warnings, and conduct rescues. Developed with techniques known as "deep learning", the Shark Spotter system receives imagery from the drone camera and attempts to identify all objects in the scene. Once certain objects are detected, they are put into one of 16 categories: shark, whale, dolphin, rays, different types of boats, surfers, and swimmers.

    If a shark is detected, Shark Spotter provides both a visual sign on the computer screen and an audible warning to the operator. The operator confirms the warning and sends text messages from the Shark Spotter system to the Surf Life Savers for further action. In an emergency, the drone is equipped with a lifesaving flotation pod (漂浮仓) together with an electronic shark repellent (驱逐装置) that can be dropped into the water in cases where swimmers are in severe trouble, trapped in a rip, or if there are sharks close by.

    In January 2018, the Westpac Little Ripper Lifesavers was used to rescue two young swimmers caught in a rip at Lennox Head, NSW. The drone flew down the beach some 800 meters from the lifeguard station, and a lifesaving flotation pod was dropped from the drone. The complete rescue operation took 70 seconds.

    We believe Shark Spotter is a win-win for both marine life and beachgoers. This unique technology combines dynamic video image processing AI and advanced drone technology to creatively deal with the global challenge of ensuring safe beaches, protecting environments, and promoting tourism.

Feeling achy and feverish? Your misery has plenty of company. By the end of December, the tally(记录) of flu-like illnesses in the state exceeded the peaks in the two previous seasons, when the biggest number of cases occurred in February and March. This time, the flu virus seems to be hitting even harder.

Flu is unique among human diseases. It circulates constantly in cool and dry areas. Because it spreads from person to person and can be picked up easily, nearly everyone is exposed. While it's unclear whether the annual flu epidemic(流行病) will worsen this year, or just arrived earlier, fears have been increased by the severity of flu in Australia during its most recent season and the fact that the vaccine may protect against the predominant(盛行的) kind of the flu only 30 percent of the time.

Despite the worries, doctors and public health officials say there is no evidence that people are getting sicker than usual. Flu cases in Massachusetts started rising around Thanksgiving and increased steadily, with an especially steep climb in the last week of the year. "This is a bad flu season but not a horrible one," said Dr Andrew G. Villanueva, a lung specialist and chief quality officer at the Lahey Hospital & Medical Centre in Burlington.

"The flu season, while clearly in full swing, doesn't ‘feel different' from previous years," Villanueva said. "We're not seeing a lot of people being hospitalised because of flu," he said. "Most people with the flu recover on their own without medical care."