After a terrible electrical accident, which caused him to become both blind and deaf, the whole world became completely dark and quiet for Robert Edwards for almost ten years. The loss of sight and hearing threw him into such sorrow that he tried a few times to put an end to his life. His family, especially his wife, did their best to tend and comfort him and finally he regained the will to live.

    One hot summer afternoon, he was taking a walk with a stick near his house when a thunderstorm started all at once. He stood under a large tree to avoid getting wet, but he was struck by the lightning. Witnesses thought he was dead but he woke up some 20 minutes later lying face down in muddy water at the base of the tree. He was trembling badly, but when he opened his eyes, he could hardly believe what he saw：a plough and a wall. When Mrs. Edwards came running up to him，shouting to their neighbors to call for help，he could see her and hear her voice for the first time in nearly ten years.

    The news of Robert regaining his sight and hearing quickly spread, and many doctors came to examine him. Most of them said that he regained his sight and hearing from the shock he got from the lightning. However, none of them could give a convincing answer as to why this should have happened. The only reasonable explanation given by one doctor was that, since Robert lost his sight and hearing as a result of a sudden shock, perhaps, the only way for him to regain them was by another sudden shock.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    China is the biggest market in the world, and many countries such as Germany, the USA, the UK and Russia do a lot of business in China. Let's have a look at some important tips to help you be successful when dealing with these nationalities.

    First, you must be punctual (准时的) with Germans. Even 5 minutes late makes a bad impression. Being punctual is also very important in the USA. In the UK, it's important to be punctual for business meetings, but nobody expects you to be on time for a social event. Half past seven really means a quarter to eight, or even eight o'clock! With Russians, you should always be on time, though it is not unusual for them to be one or even two hours late!

    It is best to dress formally and wear dark colours when you meet people from all the four countries. In Russia, designer clothes are very common. Don't be surpri if you go to an office in the UK on a Friday and find everyone wearing jeans. Many companies have “dress down Friday”, when people wear casual (随便的) clothes.

    In Germany, first names are only used by family members and close friends, so be prepared to use titles and last names. In the USA you will usually be invited to use first names almost immediately. The British are quite informal and using first names in business is more and more common, especially among younger people. In Russia, however, nobody uses first names, so use titles and last names.

    In conversation, the British and the Americans value humour, and both like to talk about sport. The weather is also a good topic of conversation with the British and the Americans, but avoid talking about politics. In Russia, say positive（肯定的） things about their country, but avoid making complaints. The Germans, however, prefer to get straight down to business!

    So, use these tips, and you will be on your way to a successful international business career!

    The human brain contains 10 thousand million cells and each of these may have a thousand connections. Such enormous numbers used to discourage us and cause us to dismiss the possibility of making a machine with human-like ability, but now that we have grown used to moving forward at such a pace we can be less sure. Quite soon, in only 10 or 20 years perhaps, we will be able to assemble a machine as complex as the human brain, and if we can we will. It may then take us a long time to render it intelligent by loading in the right software (软件)or by altering the architecture but that too will happen.

    I think it certain that in decades, not centuries, machines of silicon (硅) will arise first to compete and then do better than their human ancestors. Once they do better than us they will be capable of their own design. In a real sense they will be able to reproduce themselves. Silicon will have ended carbon's long control. And we will no longer be able to claim ourselves to be the finest intelligence in the known universe.

    As the intelligence of robots increases to match that of humans and as their cost declines through economies of scale we may use them to improve environments. Thus, deserts may bloom and the ocean beds be mined. Further ahead, by a combination of the great wealth this new age will bring and the technology it will provide, the construction of a vast, man-created world in space, home to thousands or millions of people, will be within our power.

How to Prevent Dehydration

    When the weather's warm, you need to make sure you drink enough water. But did you know that you lose your sense of thirst as you get older? This means you5re more likely to become dehydrated, making you more prone to (有倾向) falls, heart disease, urinary-tract infections, kidney stones and confusion. A study from Loughborough University in the UK has shown that drivers who had only a little water an hour made twice as many mistakes as motorists who were properly hydrated. In fact, they made a similar number of errors to what you'd expect from someone over the drink-drive limit.

    So how do you know when you're dehydrated? Warning signs include:

    Feeling tired

    Dry mouth and dry skin

    Dark urine

    Reduced appetite (食欲)

    Reduced concentration

    Headache

    Constipation.

    But you might not notice any symptoms (症状)at all，so to make sure you stay hydrated:

    Keep a glass of water by your side when you're at home, and drink it regularly.

    Form a new drinking habit—for example, when watching TV, always reach for the water glass during an ad break.

    Take a small bottle of water with you when you go out.

    Always drink a large glass of water with a meal.

    Eat fruit and vegetables with high water content.

    Draw up a weekly water card—a bit like a coffee loyalty card—with a target of eight glasses of water a day. Mark it every time you have a glass of water. Award yourself a prize when ifs full at the end of the week.

    Drink water before, during and after you take any exercise.

    Will it matter if you don't take your breakfast? A short time ago, a test was given in the United States. People of different ages, from 12 to 83, were asked to have a test. During the test, these people were given all kinds of breakfast, and sometimes they got no breakfast at all. Scientists wanted to see how well their bodies worked when they had eaten different kinds of breakfast.

    The results show that if a person eats a right breakfast, he or she will work better than if he or she has no breakfast. If a student has fruit, egg, bread and milk before going to school, he or she will learn more quickly and listen more carefully.

    The result is opposite to what some people think. Having no breakfast will not help you lose weight. This is because people become so hungry at noon that they eat too much for lunch. They will gain weight (增加体重) instead of losing it. You will lose more weight if you decrease your other meals.

    Scientists recently discovered that pictures on cave walls at Creswell Crags are the oldest known in Great Britain. But they didn't find out in the usual way.

    Archaeologists often date cave art with a process called radiocarbon dating. The technique can measure the age of carbon found in charcoal (木炭) drawings or painted pictures. Carbon is an element found in many things, including charcoal and even people. But in this case, there was no paint or charcoal to test. People carved the pictures of animals and figures into the rock using stone tools. The scientists had an "aha!" moment when they noticed small rocks stuck to the top of the drawings. The small rocks must have formed after the drawings were made.

    "It is rare to be able to scientifically date rock art," said Alistair Pike, an archaeological scientist at Britain's University of Bristol. "We were very fortunate that some of the engravings were covered by stalagmites(石笋).

    When a test proved that the stalagmites formed 12,800 years ago, the scientists knew the art underneath them had to be at least that old. And some of the animals shown, like the European bison, are now extinct-another tip-off that the art is quite old.

    The artists came to Creswell Crags, This place is one of the farthest points north reached by our ancient ancestors during the Ice Age. At that time, much of the North Sea was dry, so people could move about more easily.

    Some tools and bones found there are 13,000 to 15,000 years old. They show that the travelers hunted horses, reindeer, and arctic hare. Their artwork is similar to art in France and Germany. It tells scientists that the Creswell Crags artists must have had a close connection to peoples several thousand kilometers away—another important clue to understanding how humans spread out across the world.