If a diver surfaces too quickly, he may suffer the bends. Nitrogen (氮) dissolved (溶解) in his blood is suddenly liberated by the reduction of pressure. The consequence, if the bubbles (气泡) accumulate in a joint, is sharp pain and a bent body—thus the name. If the bubbles form in his lungs or his brain, the consequence can be death.

    Other air-breathing animals also suffer this decompression (减压) sickness if they surface too fast: whales, for example. And so, long ago, did ichthyosaurs. That these ancient sea animals got the bends can be seen from their bones. If bubbles of nitrogen form inside the bone they can cut off its blood supply. This kills the cells in the bone, and consequently weakens it, sometimes to the point of collapse. Fossil (化石) bones that have caved in on themselves are thus a sign that the animal once had the bends.

    Bruce Rothschild of the University of Kansas knew all this when he began a study of ichthyosaur bones to find out how widespread the problem was in the past. What he particularly wanted to investigate was how ichthyosaurs adapted to the problem of decompression over the 150 million years. To this end, he and his colleagues traveled the world's natural-history museums, looking at hundreds of ichthyosaurs from the Triassic period and from the later Jurassic and Cretaceous periods.

    When he started, he assumed that signs of the bends would be rarer in younger fossils, reflecting their gradual evolution of measures to deal with decompression. Instead, he was astonished to discover the opposite. More than 15% of Jurassic and Cretaceous ichthyosaurs had suffered the bends before they died, but not a single Triassic specimen (标本) showed evidence of that sort of injury.

    If ichthyosaurs did evolve an anti-decompression means, they clearly did so quickly—and, most strangely, they lost it afterwards. But that is not what Dr Rothschild thinks happened. He suspects it was evolution in other animals that caused the change.

    Whales that suffer the bends often do so because they have surfaced to escape a predator (捕食动物) such as a large shark. One of the features of Jurassic oceans was an abundance of large sharks and crocodiles, both of which were fond of ichthyosaur lunches. Triassic oceans, by contrast, were mercifully shark- and crocodile-free. In the Triassic, then, ichthyosaurs were top of the food chain. In the Jurassic and Cretaceous, they were prey (猎物) as well as predator—and often had to make a speedy exit as a result.

    Imagine a mass of floating waste is two times the size of the state of Texas. Texas has a land area of more than 678,000 square kilometers. So it might be difficult to imagine anything twice as big. All together, this mass of waste flowing in the North Pacific Ocean is known as the Great Pacific Ocean Garbage Patch（太平洋垃圾带）. It weighs about 3,500,000 tons. The waste includes bags, bottles and containers-plastic products of all kinds.

    The eastern part of the Great Pacific Ocean Garbage Patch is about 1,600 kilometers west of California. The western part is west of the Hawaiian Islands and east of Japan. The area has been described as a kind of oceanic desert, with light winds and slow moving water currents（流，流动）. The water moves so slow that garbage from all over the world collects there.

    In recent years, there have been growing concerns about the floating garbage and its effect on sea creatures and human health. Scientists say thousands of animals get trapped in the floating waste, resulting in death or injury. Even more die from a lack of food or water after swallowing pieces of plastic. The trash can also make animals feel full, diminishing their desire to eat or drink.

    The floating garbage also can have harmful effects on people. There is an increased threat of infection（感染）of disease from polluted waste, and from eating fish that swallowed waste. Divers can also get trapped in the plastic.

    Its existence first gained public attention in 1997. That was when racing boat captain and oceanographer Charles Moore and his crew sailed into the garbage while returning from a racing event. Five years earlier, another oceanographer learnt of the trash after a shipment of rubber duckies got lost at sea. Many of those toys are now part of the Great Pacific Ocean Garbage Patch.

    In August,2017, a team from the University of California, San Diego became the latest group to travel to it. They were shocked by the amount of waste they saw. They gathered hundreds of sea creatures and water samples to measure the garbage patch's effect on ocean environment.

    The Golden Gate Bridge in San Francisco, California is one of the world's most beautiful bridges. It is also one of the most visited places in the world. Vehicles(车辆)cross the bridge an average of 41 million times each year. More than 1800 hundred million vehicles have used the bridge since it opened more than 70 years ago.

    The bridge was painted "International Orange" because that color went well with the natural surroundings. The color also is easier to see in the heavy fog that often covers the area. But the Golden Gate Bridge was not named for its orange color. It was named for the body of water that it crosses，the Golden Gate Strait.

    The Golden Gate Strait is the entrance to the San Francisco Bay from the Pacific Ocean. The Golden Gate Bridge links the city of San Francisco with Marin County, California.

    Planning for the bridge began in the 1920s when the area around San Francisco was growing. People living in the area needed another way to get to the city besides small ferries(渡船).

    Joseph Strauss was the chief engineer for the project. Work began in 1934. Mr. Strauss demanded the strongest safety protections in the history of bridge building. These included the first use of "hard hats" to protect the workers' heads and special glasses to protect their eyes.

    A special safety net was suspended(挂)under the bridge. This net saved the lives of 19 men during the construction. However，11 other workers were killed when they fell from the bridge through the net. Still，this was a new safety record for the time.

    The Golden Gate Bridge opened in 1937.It extends 1280 meters across the water. The total length is 2737 meters. It was the largest suspension bridge(吊桥)in the world until 1964.That is when the Verrazano Narrows Bridge opened in New York City. Today，the Golden Gate Bridge is the ninth longest suspension bridge in the world.

Rich as a King

    William 1, who conquered England some 930 years ago, had wealth, power and an army. Yet although William was very rich by the standard of his time, he had nothing like a flush toilet (抽水马桶), paper towels, or riding lawn mower (除草机). How did he get by?

    History books are filled with wealthy people who were poor compared to me. I have storm windows, Croesus did not. Entire nations trembled before Alexander the Great, but he couldn't buy cat food. Czar Nicholas lacked an electric saw.

    Given how much better off I am than so many famous dead people, you'd think I'd be content. The trouble is that, like most people, I compare my wealth with that of living person: neighbors, school classmates, famous TV people. The greed I feel toward my friend Howard's new kitchen is not reduced by the fact that no kings ever had a refrigerator with glass doors,

    There is really no rising or falling standard of living. Over the centuries people simply find different things to feel sad about. You'd think that simply not having disease would put us in a good mood, but no we want a hot bath too.

    Of course, one way to achieve happiness would be to realize that even by today's standards the things I own are pretty nice. My house is smaller than the houses of many investment bankers, but even so it has a lot more rooms than my wife and I can keep clean.

    Besides, to people looking back at our era from a century or two in the future, these bankers' fancy counter tops and my awn worn Formica will seem equally shabby, I can't keep up with my neighbors right now. But just wait.

    Let's look at the movies we can't wait to watch in 2019:

    Dumbo (March 29)

    Dumbo is a 1941 American film produced by Walt Disney Productions. The main character is an elephant who is nicknamed "Dumbo". Dumbo is always laughed at for his big ears, and he is rejected by the other elephants. With no parent to care for him, he is alone. But in fact, he is capable of flying by using his ears as wings. A live-action adaptation of the film directed by Tim Burton is scheduled to be released on March 29, 2019.

    Shazam! (April 5)

    Shazam! is an upcoming American superhero film based on the DC Comics character of the same name. Directed by David F. Sandberg, the film is set to star Asher Angel as Billy Batson, a teenage boy who can transform via the magic word "Shazam" into an adult superhero, played by Zachary Levi. It will be the first film version of the character since the 1941 series Adventures of Captain Marvel (the character's original name).

    Aladdin (May 24)

    Aladdin is a fictional character and the role of the film Aladdin (1992) based on Aladdin, a folk tale of Middle Eastern origin. He is voiced by Scott Weinger, while his singing voice is provided by Brad Kane. Aladdin never received a formal education, and has only learned by living on the streets of Agrabah. He has to steal food in the local market in order to survive. Mena Massoud is set to play a live-action version of the character in a live action adaptation of the 1992 film.

    Godzilla, King of the Monsters (May 31)

    Godzilla, King of the Monsters is a 1956 Japanese-American science fiction film, co-directed by Terry O. Morse and Ishiro Honda. It is a heavily re-edited American adaptation. For this new version of Godzilla, some of the original Japanese dialogue was translated into English, and some of the political, social and anti-nuclear themes were removed completely.

The hens look up at me from their nesting boxes. They seem slightly annoyed but unsurprised. A child runs up, pushes one of the chickens aside, and snatches two eggs. Around me, a half-dozen more children and adults collect eggs while a half-dozen others hand-feed dried mealworms to birds flocking around our ankles. I reach for an egg from an empty nest. There is something perfect about the way it fits warmly in the palm of my hand before I transfer it into a pretty wire basket provided to me by my hosts. 

The egg harvest is a brief, carefully designed agritourism experience offering an experience of the labor rather than just having a bite of food. Snatching a few eggs and uprooting a few vegetables on the farm tour donˈt constitute a full dayˈs work, but it is also a useful reminder that food doesnˈt just magically appear on restaurant plates and grocery store shelves. Of course, visitors can take those eggs home or bring them to the on-farm restaurant, Clay, where a chef will use them to prepare breakfast. 

A few centuries of industrialization, urbanization, and globalization have collected people into cities, but the attraction of the countryside has always remained. In the new urban-centered world, enterprising farmers have found plenty of opportunities to sell their rural lifestyle along with their crops. Italy promoted the modern model for combining agriculture and tourism in the wake of World War Ⅱ, when the national government encouraged rural populations to continue producing food rather than move to urban areas in search of more profitable jobs. 

Agritourism acts as an umbrella term for a wide variety of activities that take place on farms, including farmstays, where guests sleep on-site. For varying investments of time, energy, and money, anyone can engage in our farming system, giving consumers a peek behind the farm-to-table world.