问答题You can learn something about a place by reading a travel book, but you learn more when you actually travel there.

问答题People remember emotionally charged events more easily than they recall the quotidian. A sexual encounter trumps doing the grocery shopping. A mugging trumps a journey to work. Witnessing a massacre trumps pretty well anything you can imagine. That is hardly surprising. Rare events that might have an impact on an individual's survival or reproduction should have a special fast lane into the memory bank—and they do. It is called the α2b-adrenoceptor, and it is found in the amygdala, a part of the brain involved in processing strong emotions such as fear. The role of the α2b-adrenoceptor is to promote memory formation—but only if it is stimulated by adrenaline. Since emotionally charged events are often accompanied by adrenaline secretion, the α2b-adrenoceptor acts as a gatekeeper that decides what will be remembered and what discarded. However, the gene that encodes this receptor comes in two varieties. That led Dominique de Quervain, of the University of Zurich, to wonder if people with one variant would have better emotional memories than those with the other. The short answer, just published in Nature Neuroscience, is that they do. Moreover, since the frequencies of the two variants are different in different groups of people, whole populations may have different mixtures of emotional memory. The reason Dr. de Quervain suspected the variants might work differently is that the rarer one looks like the commoner one when the latter has a memory-enhancing drug called yohimbine attached to it. His prediction, therefore, was that better emotional memory would be associated with the rarer version. And that did, indeed, turn out to be the case in. his first experiment. This involved showing students photographs of positive scenes such as families playing together, negative scenes such as car accidents, and neutral ones, such as people on the phone. Those students with at least one gene for the rarer version of the protein (everyone has two such genes, one from his father and one from his mother) were twice as good at remembering details of emotionally charged scenes than were those with only the common version. When phone-callers were the subject, there was no difference in the quality of recall. That is an interesting result, but some of Dr. de Quervain's colleagues at the University of Konstanz, in Germany, were able to take it further in a second experiment. In fact, they took it all the way along a dusty road in Uganda, to the Nakivale refugee camp. This camp is home to hundreds of refugees of the Rwandan civil war of 1994. In this second experiment the researchers were not asking about photographs. With the help of specially trained interviewers, they recorded how often people in the camp suffered flashbacks and nightmares about their wartime experiences. They then compared those results with the α2b-adreno-ceptor genes in their volunteers. As predicted, those with the rare version had significantly more flashbacks than those with only the common one. Besides bolstering Dr. de Quervain's original hypothesis, this result is interesting because only 12% of the refugees had the rarer gene. In Switzerland, by contrast, 30% of the population has the rare variety—and the Swiss are not normally regarded as an emotional people. Whether that result has wider implications remains to be seen. Human genetics has a notorious history of jumping to extravagant conclusions from scant data, but that does not mean conclusions should be ducked if the data are good. In this case, the statistics suggest Rwanda may have been lucky: the long-term mental-health effects of the war may not be as widespread as they would have been in people with a different genetic mix. On the other hand, are those who easily forget the horrors of history condemned to repeat them?

问答题自1978年中国实行儿童计划免疫以来，中国儿童的健康发展水平和营养状况不断提高。

问答题The footwear manufacturing industry is made up predominantly of small companies, increasingly under pressure from imports.

问答题Besides teaching teenagers to protect their computers, the course opens their imagination to the challenges in cyberspace, and seeks to excite them into a college education in computer engineering and a professional career in cyber security.

问答题人们坚信奥林匹克的理念，相信有健康的体魄才有健康的头脑，运动竞技的精神比引爆战争的恶性竞争更为可取。

问答题Walk along the River Warnow, in northern Germany, and you may be lucky enough to spot a SeaFalcon, a sleek, white machine with two propellers, two wings and a distinctly unbirdlike tail. It looks like an aircraft. Which is what it is. Except, it isn"t. It is a ship—at least in the eyes of the International Marine Organisation, which regulates such things. That matters, because ships are much more lightly regulated than aircraft. The SeaFalcon is really a ground-effect vehicle. It flies only over water and only two metres above that water. This means the air beneath its wings is compressed, giving it additional lift. In effect, it is floating on a cushion of air. That makes it far cheaper to run than a plane of equivalent size, while the fact that it is flying means it is far faster—at 80-100 knots—than a ship of any size. Its designer, Dieter Puls, thus hopes it will fill a niche for the rapid transport of people and light goods in parts of the world where land and sea exist in similar proportions. The theory of ground-effect vehicles goes back to the 1920s, when Carl Wieselsberger, a German physicist, described how the ground effect works. There was then a period of silence, followed by a false start. In the 1960s the Soviet armed forces thought that ground-effect vehicles would be ideal for shifting heavy kit around places like the Black Sea. Their prototypes did fly, but were never deployed in earnest and their jet engines consumed huge amounts of fuel. This did, however, prove that the idea worked. And two German engineers, Mr. Puls and Hanno Fischer (whose version is called Airfish 8), have taken it up and made it work by using modern, composite materials for the airframes, and propellers rather than jets for propulsion. One reason the Soviet design was so thirsty is that the power needed to lift a ground-effect vehicle is far greater than that needed to sustain it in level flight. The Soviet design used heavy jet engines to deliver the power needed for take-off. But the SeaFalcon uses a hydrofoil to lift itself out of the water, and Airfish 8 uses what Mr. Fischer calls a hoverwing—a system of pipes that takes air which has passed through the propeller and blasts it out under the craft during take-off. The next stage, of course, is to begin production in earnest—and that seems to be about to happen. Mr. Puls says he has signed a deal with an Indonesian firm for an initial order of ten, while both he and Mr. Fischer are in discussions with Wigetworks, a Singaporean company, with a view to starting production next year. South-East Asia, with its plethora of islands and high rate of economic growth is just the sort of place where ground-effect vehicles should do well. All of which sounds optimistic. But a note of caution is needed. For another sort of ground-effect vehicle was also expected to do well and ended up going nowhere. The hovercraft differed from the vehicles designed by Messrs Puls and Fischer in that it relied on creating its own cushion of air, rather than having one provided naturally. That meant it could go on land as well as sea—which was thought at the time (the 1950s) to be a winning combination. Sadly, it was not. Hovercraft have almost disappeared. But then, in the eyes of the regulators, they counted as aircraft.

问答题他承认有不少国家和公众对中国还存在理解上的不足。

问答题我担心他会把我拽下去，这使我高度紧张。

问答题同行是冤家。

问答题由于各方在发展中国家提高农产品关税这一问题上无法达成一致，上个月在日内瓦会议举行的多哈(Doha)回合谈判最终破裂。

问答题例如，放射性的铷的一个原子退化后，把一个中子转变成一个质子并释放出一个电子，形成一个锶(另外一种元素)原子，在这个过程中产生能量。退化后的放射性子产品——在这里就是锶原子——会以一个极高的温度分散化解。所以测量一下现在矿物中铷原子和锶原子的确切比例，研究人员就会推导出该矿物在冷却到凝结温度以下之后又埋没了多少年。这种回溯方法具有弊端，因为很难发现含有铷元素的矿物、测量铷元素和锶元素的精确比例，而且推断出的时间只是矿物最后冷却到凝结温度之下的时间。因为凝结温度很高，这种方法只适用于再结晶岩石(火成岩或变质岩)，不适合沉积岩——含铷元素的矿质，它能记载岩石腐化成沉积物的冷却时间，而不是沉积物自己的蜕变年龄。

问答题Imagine fishermen walking down to the seashore, ready to carry out their early morning routine of preparing their boats and net. As usual they hope for a good catch of fish. But to their astonishment, a horrible sight meets their still sleepy eyes. Thousands of fish have been washed ashore dead. The cause of this mass destruction? A red tide! Red tides are a global phenomenon, They have been observed on both the Atlantic and the Pacific coasts of the United States and Canada. They have also occurred in many other places. Though relatively few people are aware of them, red tides are not new. In the Philippines, a red tide was first seen in the province of Bata an in 1908. Since then, red tides have been seen in many other coastal areas A Philippines red tide expert told us that "besides the fish kills, the Philippines has documented 1,926 eases of dead shellfish poisoning caused by red tides." The term "red tide" applies to the discoloration of water that sometimes occurs in certain areas of the ocean or sea. Although the color is often red, it may also be shades of brown or yellow. The World Book Encyclopedia reports that "the discolored areas may range from less than a few square yards to more than 2,600 square kilometers." What causes such discoloration? Red tides are generally caused by several species of single-celled organisms. These tiny organisms have hair-like projections which they use to propel them-selves in water. There are about 2,000 varieties of these organisms, 30 of which carry poisonous substances these minute organisms usually stay in warm waters with high content of salt. A red tide occurs when there is a sudden and rapid bloom of these organisms. The concentration of these organisms may swell to 50,000,000 per quart of water! Although scientists do not fully understand why this happens. It is known that these organisms accumulate when certain conditions simultaneously affect the water. These include abnormal weather, optimum temperatures, an over-supply of nutrients in the water, a generous amount of sunlight, and favorable water currents. When a heavy rainfall occurs, minerals and other nutrients are sometimes washed from the land into coastal water. These nutrients can contribute to the breeding of the organisms. The result? Red tides!

问答题泰勒斯认为水是万物之始；阿那克西米尼认为空气是万物之始；赫拉克利特则认为火是万物之始。(泰勒斯：Thales；阿那克西米尼：Anaximenes；赫拉克利特：Heraclitus)

问答题我进屋时，他{{U}}在读书{{/U}}。

问答题It is natural for young people to be critical of their parents at times and to blame them for most of misunderstandings between them. 16 They have always complained that their parents are out of touch with modern ways; that they are possessive and dominant; that they do not trust their children to deal with crisis. 17 It is universally acknowledged that parents often underestimate their teenage children and also fade in their memory how they themselves felt when young. Young people often irritate their parents with their choices in clothes and hairstyles, in entertainers and music. This is not their motive. 18 They feel cut off from the adult world into which they have not yet been accepted so they create a culture and society of their own. Then, if it turns out that their music or entertainers or vocabulary or clothes or hairstyles irritates their parents, this gives them additional enjoyment. They feel they are superior, at least in a small way, and that they are leaders in style and taste. Sometimes they are resistant and proud because they do not want their parents to approve of what they do. If their parents did approve, it looks as if they are betraying their own age group. But in that case, they are assuming that they are the underdog: you can"t win but at least you can keep your honor. This is a passive way of looking at things. 19 It is natural enough after long years of childhood, when they were completely under their parents" domination. But it ignores the fact that they are now beginning to be responsible for themselves. My advice to young people is as follows: if you plan to control your life, cooperation can be pan of that plan. 20 You can charm others, especially your parents, into doing things the way you want. You can impress others with your sense of responsibility and initiative, so that they will give you the authority to do what you want to do.

问答题随着我国社会经济的迅猛发展、人们生活水平的提高和医疗卫生事业的改善，我国老年人口著显增多。不少人对此忧心忡忡，但有识之士指出，我们不仅要看到人口老龄化所带来的巨大压力，也要看到人口老龄化背后所蕴涵的商机以及老年人丰富的智力、经验等资源，要将压力变为机遇。

问答题In large hospitals and research centers, modem methods of therapy seem to focus on the physical disease without considering the patient's mental state.

问答题日本直到1983年才提出要做“政治大国”。

问答题The right to food is a universal right. It means that every person -- man and woman, young and old -- must have access at all times to food, or to means for the procurement of food, that is sufficient in quality, quantity and variety to meet their needs, is free from harmful substances and is acceptable to their culture.