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.

    He's an old cobbler(修鞋匠) with a shop in the Marais, a historic area in Paris. When I took him my shoes, he at first told me: “I haven't time. Take them to the other fellow on the main street; he'll fix them for you right away.”

    But I'd had my eye on his shop for a long time. Just looking at his bench loaded with tools and pieces of leather, I knew he was a skilled craftsman(手艺人). “No,” I replied, “the other fellow can't do it well.”

    “The other fellow” was one of those shopkeepers who fix shoes and make keys “while-U-wait” — without knowing much about mending shoes or making keys. They work carelessly, and when they have finished sewing back a sandal strap(鞋带), you might as well just throw away the pair.

    My man saw I wouldn't give in, and he smiled. He looked at my shoes, had me write my name on one shoe with a piece of chalk and said, “Come back in a week.”

    I was about to leave when he took a pair of soft leather boots off a shelf.

    “See what I can do?” he said with pride. “Only three of us in Paris can do this kind of work.”

    When I got back out into the street, the world seemed brand-new to me. He was something out of an ancient legend, this old craftsman with his way of speaking familiarly, his very strange, dusty felt hat, his funny accent from who-knows-where and, above all, his pride in his craft.

    These are times when nothing is important but the bottom line, when you can do things any old way as long as it “pays”, when, in short, people look on work as a path to ever-increasing consumption(消费) rather than a way to realize their own abilities. In such a period it is a rare comfort to find a cobbler who gets his greatest satisfaction from pride in a job well done.

Metro Pocket Guide

    Metrorail (地铁)

    Each passenger needs a farecard to enter and go out. Up to two children under age five may travel free with a paying customer.

Farecard machines are in every station. Bring small bills because there are no change machines in the stations and farecard machines only provide up to $5 in change.

    Get one ticket of unlimited Metrorall rides with a One Day Pass .Buy it from a farecard machine in Metro stations .Use it after 9:30 a,m. until closing on weekdays , and all day on weekends and holidays .

Hours of service

    Open 5am Mon-Fri             7a.m Sat-Sun

    Close midnight Sun-Thurs.          3a.m. Sat-Sun

    Last train times vary .To avoid missing the last train, please check the last train time posted in the station.

    Train times Posted in stations

    Metrobus

    When paying with exact charge, the fare is $1.35.When paying with a SmatTrip card, the fare is 1.25.

    Fares for the senior/ disabled customers

    Senior citizens 65 and older and disabled customers may ride for half the regular fare .On Metrorail and Metrobus , use a senior/disabled farecard or Smar/Trip Ⓡ card .For more information about buying senior, disabled farecards, farecard or SmarTrip cards and passes , please visit MetroOpensDoors .com or call 202-637-7000and 202-637-8000.

    Senior citizens and disabled customers can get free guide on how to use proper Metrobus and Metrorall services by calling 202-962-1100.

Travel tips (提示)

    Avoid riding during weekday rush periods –before 9:30 a.m. and between 4and 6p.m.

    If you lose something on a bus or train or in a station, please call Lost &Found at 202-962-1195, Avoid riding during weekday rush periods –before 9:30 a.m. and between 4and 6p.m.

    If you lose something on a bus or train or in a station, please call Lost &Found at 202-962-1195.

    Now, more than ever before, people are wondering what life is all about, and what it is for. Seeking material success is beginning to trouble large numbers of people around the world. They feel that the long-hours work culture to make more money to buy more things is eating up their lives, leaving them very little time or energy for family or pastimes. Many are turning to other ways of living and downshifting is one of them.

    Six percent of workers in Britain took the decision to downshift last year. One couple who downshifted is Daniel and Liz. They used to work in central London. He was a newspaper reporter and she used to work for an international bank. They would go to work by train every day from their large house in the suburbs, leaving their two children with a nanny(保姆). Most evenings Daniel wouldn't get home until eight or nine o'clock, and nearly twice a month he would have to fly to New York for meetings

    They both earned a large amount of money but began to feel that life was passing them by.

    Nowadays, they run a farm in the mountains of Wales, I always wanted to have a farm here, says Daniel, "and we took almost a year to make the decision to downshift. It's taken some getting used to, but it's been worth it. We have to think twice now about spending money in car repairs and we no longer have any holidays. However, I think it's made us stronger as a family, and the children are a lot happier."

    Liz, however, is not quite sure. "I used to enjoy my job, even though it was hard work and long hours. I'm not really a country girl, but I suppose I'm gradually getting used to looking after the animals. One thing I do like, though, is being able to see more of my children. My advice for other people wanting to do the same is not to think about it too much or you might not do it at all."

Large meals make people full and sleepy. {#blank#}1{#/blank#} We want our children to learn, not falling asleep at their desks, so let's keep those lunches on the lighter side. You can do this if you provide them with a good breakfast.

By working beside your children and discussing what they eat for lunch, you are helping them understand the importance of whole foods and the avoidance of junk foods. {#blank#}2{#/blank#} As they get older, these good habits will stay with them. They will learn that these types of food are beneficial to them. Try to let them see that the food choices they are making will help them feel so much better.

{#blank#}3{#/blank#} I know of one family that actually had the food pyramid on the wall of their kitchen and it helped their children pick out what foods they wanted. Everyone got a chance to decide what to eat, but they had to pick protein, vegetables and fruit. Besides, the mother had a book with recipes for healthy foods. All of the recipes had pictures of what the food looked like. {#blank#}4{#/blank#}.

Unlike today, when we grew up we played outside, rode our bikes, ran around, and the list goes on and on. {#blank#}5{#/blank#} So apart from the above healthy eating choices, you need to plan some activities for your children today other than the television or video games.

A. We didn't have TV or computer games.

B. How are children helped to choose their food?

C. You are helping them make smart informed choices.

D. Think what large meals do to your children at school.

E. What adults eat daily has a great effect on their children.

F. So children knew what healthy foods they should choose.

G. The recipes for children should mainly include healthy foods.

With gas prices rising and airport security lines snaking longer than ever, why not book your next domestic vacation on a train? Compared to other alternatives, it's comfortable and relaxing. Here is some advice on how to make a trip by rail as pleasant as possible. 

Plan ahead. Most long-distance trains, especially the sleeping car accommodations, sell out very quickly.{#blank#}1{#/blank#}But no matter when you travel, it's a good idea to make your reservations at least 90 days in advance. 

Use a travel agent. Consider turning your travel plan over to a travel agent and letting him double-check all the details, make suggestions, and then handle the actual reservations. A good one can sometimes find you discounted tickets.{#blank#}2{#/blank#}Then you won't have to walk through several cars on a moving train three times a day for your meals. 

Bring a blanket.When you're riding on trains, you won't be provided with a blanket for free, even if your trip is an overnight one.{#blank#}3{#/blank#}In the summer in particular, the air conditioning can make them quite cold. 

Arrive early. Most trains operate just once a day and some run only three times a week, so missing yours can be a disaster.{#blank#}4{#/blank#}Note: The times listed on the schedules are departure times, not arrival times. 

Have fun.{#blank#}5{#/blank#}Read a book, knit, do a crossword puzzle, or simply watch the world unfold outside the window. To calculate your speed as you do, divide 3,600(the number of seconds in an hour)by the number of seconds it takes you to travel one mile(the distance between two mileposts). If it takes the train 53 seconds to travel one mile, you're going 67.92 mph.

A.Train trips aren't for impatient types.

B.You'll have views from both sides of the train.

C.The temperature on rail cars is often hard to control.

D.That's particularly true during busy summer months.

E.You might have to wait longer than 24 hours to catch the next one.

F.Chances are the cost will be a lot less than the cost of one bedroom.

G.He may also book you in a sleeping car that's right next to the diner.