The need to feed a growing population is putting much pressure on the world's supply of water. With 97% of the world's water too salty to be drunk or used in agriculture, the worldwide supply of water needs careful management, especially in agriculture. Although the idea of a water shortage(短缺)seems strange to someone fortunate enough to live in a high rainfall country, many of the world's agricultural industries experience constant water shortages.

    Although dams can be built to store water for agricultural use in dry areas and dry seasons, the costs of water redistribution(重新分配)are very high. Not only is there the cost of the engineering itself, but there is also an environmental cost to be considered. Where valleys(山谷)are flooded to create dams, houses are lost and wildlife homes destroyed. Besides, water may flow easily through pipes to fields, but it cannot be transported from one side of the world to the other. Each country must therefore rely on the management of its own water to supply its farming requirements. This is particularly troubling for countries with agricultural industries in areas dependent on irrigation. In Texas, farmers' overuse of irrigation water has resulted in a 25% reduction of the water stores.

    In the Central Valley area of southwestern USA, a huge water engineering project provided water for farming in dry valleys, but much of the water use has been poorly managed.

    Saudi Arabia's attempts to grow wheat in desert areas have seen the pumping of huge quantities of irrigation water from underground reserves. Because there is no rainfall in these areas, such reserves can only decrease, and it is believed that fifty years of pumping will see them run dry.

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    After returning from her round trip, the angry woman stood outside the ticket office of the station. “The railway owes me 12 pounds，” she said to Harry Jenks, the young man working at the office. “You sold me a ticket for May 22nd, but there was no ship from Jersey that night. So my daughter and I had to stay in a hotel. It cost me 12 pounds.”

    Harry was worried. He remembered selling the woman a return ticket. “Come into the office, Madam，” he said politely. “I'll just check the Jersey timetable for May 22nd.”

    The woman and her little girl followed him inside. She was quite right, as Harry soon discovered. There was no sailing on May 22nd. How could he have made such a careless mistake? He shouldn't have sold her a ticket for that day. Wondering what to do, he smiled at the child. “You look sunburnt，” he said to her. “Did you have a nice holiday in Jersey？”

    “Yes，” she answered, shyly. “The beach was lovely. And I can swim too！”

    “That's fine，” said Harry. “My little girl can't swim a bit yet. Of course，she's only three ...”

    “I'm four，” the child said proudly. “I'll be four and a half.”

    Harry turned to the mother. “I remember your ticket, Madam，” he said. “But you didn't get one for your daughter, did you？”

    “Err, well ...” the woman looked at the child. “I mean …, she hasn't started school yet. She's only four.”

    “A four-year-old child must have a ticket, Madam. A child's return ticket from Jersey costs .., let me see ... 13.50 pounds. The law is the law, but since the mistake is mine ...”

    The woman stood up, took the child's hand and left the office.

    If a trip to Rome or Paris is in your future, be prepared: The European Union Parliament is calling for an end to visa-free travel Americans. EU lawmakers passed a resolution urging the EU Commission to impose visas on U. S. citizens traveling into the 28-nation bloc.

    The dispute(争论)centers on reciprocal treatment of travelers from EU nations and the United States. While Americans have been able to travel throughout EU member nations without a visa, the U. S. still requires citizens of five EU countries-Bulgaria, Croatia, Cyprus, Poland and Romania-to apply for entry visas when visiting the U. S, Reuters reports. Citizens of the other 23 EU member nations can use the U. S. visa waiver program to enter America. The EU lawmakers are calling for mutual treatment for all EU citizens, says Reuters. They've given the EU Commission two months to respond.

    The trans-Atlantic visa dispute first came to light in April 2014, according to an EU Parliament news release. At that time, five countries-Australia, Brunei, Canada, Japan and the U. S. –required visas for some EU citizens. Since then, Australia, Brunei and Japan have lifted their visa requirements for all EU citizens. Canada, which currently imposes(推行)visa requirements on Bulgarian and Romanian citizens, plans to follow suit in next December, leaving just the United States at odds with the issue of reciprocity of visa-free travel with the EU.

The EU says if a visa requirement for Americans is introduced, it would be temporary, according to a story in Money, which did not give a time frame.

    Since English biologist Charles Darwin published On the Origin of Species in 1859, scientists have vastly improved their knowledge of natural history. However, a lot of information is still of the speculation, and scientists can still only make educated guesses at certain things.

    One subject that they guess about is why some 400 million years ago, animals in the sea developed limbs (肢) that allowed them to move onto and live on land.

    Recently, an idea that occurred to the US paleontologist (古生物学家) Alfred Romer a century ago became a hot topic once again.

    Homer thought that tidal (潮汐的) pools might have led to fish gaining limbs. Sea animals would have been forced into these pools by strong tides. Then, they would have been made either to adapt to their new environment close to land or die. The fittest among them grew to accomplish the transition (过渡) from sea to land.

    Romer called these earliest four-footed animals “tetrapods”. Science has always thought that this was a credible theory, but only recently has there been strong enough evidence to support it.

    Hannah Byrne is an oceanographer (海洋学家) at Uppsala University in Sweden. She announced at the 2018 Ocean Sciences Meeting in Oregon, US, that by using computer software, her team had managed to link Homer's theory to places where fossil deposits (沉积物) of the earliest tetrapods were found.

    According to the magazine Science, in 2014, Steven Balbus, a scientist at the University of Oxford in the UK, calculated that 400 million years ago, when the move from land to sea was achieved, tides were stronger than they are today. This is because the planet was 10 percent closer to the moon than it is now.

    The creatures stranded in the pools would have been under the pressure of “survival of the fittest”, explained Mattias Green, an ocean scientist at the UK's University of Bangor. As he told Science, “After a few days in these pools, you become food or you run out of food... the fish that had large limbs had an advantage because they could flip (翻转) themselves back in the water.”

    As is often the case, however, there are others who find the theory less convincing. Cambridge University's paleontologist Jennifer Clark, speaking to Nature magazine, seemed unconvinced. “It's only one of many ideas for the origin of land-based tetrapods, any or all of which may have been a part of the answer,” she said.

    Two of the saddest words in the English language are "if only". I live my life with the goal of never having to say those words, because they convey regret, lost opportunities, mistakes, and disappointment.

    My father is famous in our family for saying, "Take the extra minute to do it right." I always try to live by the "extra minute" rule. When my children were young and likely to cause accidents, I always thought about what I could do to avoid an "if only" moment, whether it was something minor like moving a cup full of hot coffee away from the edge of a counter, or something that required a little more work such as taping padding (衬垫) onto the sharp comers of a glass coffee table.

    I don't only avoid those "if only" moments when it comes to safety. It's equally important to avoid "if only" in our personal relationships. We all know people who lost a loved one and regretted that they had foregone an opportunity to say "I love you" or "I forgive you." When my father announced he was going to the eye doctor across from my office on Good Friday, I told him that it was a holiday for my company and I wouldn't be here. But then I thought about the fact that he's 84 years old and I realized that I shouldn't give up an opportunity to see him. I called him and told him I had decided to go to work on my day off after all.

    I know there will still be occasions when I have to say "if only" about something, but my life is definitely better because of my policy of doing everything possible to avoid that eventuality. And even though it takes an extra minute to do something right, or it occasionally takes an hour or two in my busy schedule to make a personal connection, I know that I'm doing the right thing. I'm buying myself peace of mind and that's the best kind of insurance for my emotional well-being.

    People You've Never Heard of Who Changed the World

    It is a fact that most people live their lives unremarked by history. Whether by design or by accident, there are some pioneers whose achievements changed the course of history but whose names are unknown to us.

    James Harrison

    James Harrison has saved the lives of over two million people by donating his blood 1,173 times, a Guinness world record. His blood produces a rare antibody (抗体) which cures the otherwise deadly Rhesus disease in unborn children. It has also been used in the development of a medicine anti-D, which will cure the Rhesus disease in children forever.

    Lewis Latimer

    After helping Alexander Graham Bell obtain his patent for the telephone, Lewis Latimer patented a carbon filament (碳灯丝), which allowed light bulbs to burn for hours before burning out, much more useful than that invented by Thomas Edison. Latimer went on to invent many other useful devices, including a device which cooled and cleaned patients' rooms in hospitals.

    Maurice Hilleman

    Not all achievements require bravery and self-sacrifice. Take Maurice Hilleman for example. He found another way to change the world. He developed the mumps vaccine (疫苗) after his daughter got the illness. And he didn't stop there. In total, he has single-handedly developed over 40 vaccines, including eight commonly given to children. His work has saved millions of lives and prevented serious consequences due to the diseases.

    Nils Bohlin

    In 1959 Nils Bohlin patented a revolutionary design that has saved millions of lives－the three-point safety belt. After the initial resistance from drivers who hated being told what to do, and even for their own good, the three-point belt has become a standard feature in new cars around the world.