Before a big exam, a sound night’ s sleep will do you better than poring over textbooks. That, at least, is the folk wisdom. And science, in the form of behavioral psychology, supports that wisdom. But such behavioral studies cannot distinguish between two competing theories of why sleep is good for the memory. One says that sleep is when permanent memories form. The other says that they are actually formed during the day, but then “edited“ at night, to flush away what is superfluous. To tell the difference, it is necessary to look into the brain of a sleeping person, and that is hard. But after a decade of painstaking work, a team led by Pierre Maquet at Liege University in Belgium has managed to do it. The particular stage of sleep in which the Belgian group is interested is rapid eye movement(REM)sleep, when brain and body are active, heart rate and blood pressure increase, the eyes move back and forth behind the eyelids as if watching a movie, and brainwave traces resemble those of wakefulness. It is during this period of sleep that people are most likely to relive events of the previous day in dreams. Dr. Maquet used an electronic device called PET to study the brains of people as they practiced a task during the day, and as they slept during the following night. The task required them to press a button as fast as possible, in response to a light coming on in one of six positions. As they learnt how to do this, their response times got faster. What they did not know was that the appearance of the lights sometimes followed a pattern—what is referred to as “ artificial grammar“. Yet the reductions in response time showed that they learnt faster when the pattern was present than when there was not. What is more, those with more to learn(i. e. the “grammar“ , as well as the mechanical task of pushing the button)have more active brains. The “editing“ theory would not predict that, since the number of irrelevant stimuli would be the same in each case. And to eliminate any doubts that the experimental subjects were learning as opposed to unlearning, their response times when they woke up were even quicker than when they went to sleep. The team, therefore, concluded that the nerve connections involved in memory are reinforced through reactivation during REM sleep, particularly if the brain detects an inherent structure in the material being learnt. So now, on the eve of that crucial test, maths students can sleep soundly in the knowledge that what they will remember the next day are the basic rules of algebra and not the incoherent talk from the radio next door.

When did the woman give up smoking?M: Cigarette? W: No, thank you. I’ve given up, you know. M: Oh. W: It’ s ten days ago. Haven’t had one. M: Well, you don’t mind if I had one. W: Well, all right, then. . . Oh my goodness! That’ s a terrible cough. M: No, no, it’ s not. It’ s only. . . I only get it first thing in the morning. W: That’ s going to make you very unfit, you know. M: No, it’ s all right. It goes in a minute. W: Why don’t you try and give up? M: Oh, no. I ought to, but I can’t. It relaxes me, smoking. W: Really? M: It does. W: Well, have you ever thought of just cutting down? M: Oh, no, that’ s all very well but. . . I wouldn’ t enjoy it. I depend a bit on my smoking. I must say. W: You should do it gradually. I mean. . . well, if you tried. . . have you thought of just giving up one day? M: Yes, oh well, yes, that is quite a good idea. W: It is. M: But I think I’ d lose count or something. W: Oh dear! Well, it might be an idea if you started eating sweets. M: Oh no, I couldn’ t do that. I couldn’ t possibly. . . W: Why? M: Well, it makes you fat. W: Well, do you think that matters? Don’ t you think it is better to be fat than to be unhealthy? M: No, I don’ t. I’d rather be fat. . . Well, I’ d rather be thin than fat, certainly. W: Oh dear. Well. Hey! I’ ve got a good idea! M: What’s that? W: Why don’ t you go to a hypnotist? My sister did! M: Oh, look, you don’t seem to realize that I like smoking. If I gave it up, if I didn’ t smoke at all, I’d probably end up attacking people! W: Oh, don’ t be so silly! Of course you wouldn’ t! Ten days ago. Just this morning. A week ago. Just yesterday.

What is this passage mainly about?The human nose has given to the languages of the world many interesting expressions. Of course, this is not surprising. Without the nose, we could not breathe nor smell. It is a part of the face that gives a person special character. Cyrano de Bergerac said that a large nose showed a great man courageous, courteous, manly, and intellectual. A famous woman poet wished that she had two noses to smell a rose! Blaise Pascal, a French philosopher, made an interesting comment about Cleopatra’s nose. If it had been shorter, he said, it would have changed the whole face of the world! Historically, man’s nose has had a principal role in his imagination. Man has referred to the nose in many ways to express his emotions. Expressions concerning the nose refer to human weakness;anger, pride, jealousy and revenge. In English there are a number of phrases about the nose. For example, to hold up one’s nose expresses a basic human feeling—pride. People can hold up their noses at people, things, and places. The phrase, to be led around by the nose, shows man’s weakness. A person who is led around by the nose lets other people control him. On the other hand, a person who follows his nose lets his instinct guide him. For the human emotion of rejection, the phrase to have one’s nose put out of joint is very descriptive. The expression applies to persons who have been turned aside because of a rival. Their pride is hurt and they feel rejected. This expression is not new. It was used by Erasmus in 1542. This is only a sampling of expressions in English dealing with the nose. There are a number of others. However, it should be as plain as the nose on your face that the nose is more than an organ for breathing and smelling! The human nose as an organ for breathing and smelling. The nose providing us with various expressions. A woman poet’s wish to have two noses. Interesting comments made on Cleopatra’s nose.

Defenders of special protective labor legislation for women often maintain that eliminating such laws would destroy the fruits of a century-long struggle for the protection of women workers. Even a brief examination of the historic practice of courts and employers would show that the fruit of such laws has been bitter; they are, in practice, more of a curse than a blessing. Sex-defined protective laws have often been based on stereotypical assumptions concerning women’ s needs and abilities, and employers have frequently used them as legal excuses for discriminating against women. After the Second World War, for example, businesses and government sought to persuade women to vacate jobs in factories, thus making room in the labor force for returning veterans. The revival or passage of state laws limiting the daily or weekly work hours of women conveniently accomplished this. Employers had only to declare that overtime hours were a necessary condition of employment or promotion in their factory, and women could be quite legally fired, refused jobs, or kept at low wage levels, all in the name of “protecting“ their health. By validating such laws when they are challenged by lawsuits, the courts have colluded over the years in establishing different, less advantageous employment terms for women than for men, thus reducing women’ s competitiveness on the job market. At the same time, even the most well-intentioned lawmakers, courts, and employers have often been blind to the real needs of women. The lawmakers and the courts continue to permit employers to offer employee health insurance plans that cover all known human medical disabilities except those relating to pregnancy and childbirth. Finally, labor laws protecting only special groups are often ineffective at protecting the workers who are actually in the workplace. Some chemicals, for example, pose reproductive risks for women of childbearing years; manufacturers using the chemicals comply with laws protecting women against these hazards by refusing to hire them. Thus the sex-defined legislation protects the hypothetical female worker, but has no effect whatever on the safety of any actual employee. The health risks to male employees in such industries cannot be negligible, since chemicals toxic enough to cause birth defects in fetuses or sterility in women are presumably harmful to the human metabolism. Protective laws aimed at changing production materials or techniques in order to reduce such hazards would benefit all employees without discriminating against any. In sum, protective labor laws for women are discriminatory and do not meet their intended purpose. Legislators should recognize that women are in the work force to stay, and that their needs—good health care, a decent wage, and a safe workplace—are the needs of all workers. Laws that ignore these facts violate women’ s rights for equal protection in employment.

Today TV audiences all over the world are accustomed to the sight of American astronauts in tip-top condition, with fair hair, crew-cuts, good teeth, an uncomplicated sense of humour and a severely limited non-technical vocabulary. What marks out an astronaut from his earthbound fellow human beings is something of a difficult problem. Should you wish to interview him, you must apply beforehand, and you must be prepared for a longish wait, even if your application meets with success. It is, in any case, out of the question to interview an astronaut about his family life or personal activities, Because all the astronauts have contracts with an American magazine under conditions forbidding any unauthorized disclosures about their private lives. Certain obvious qualities are needed. Anyone who would be a spaceman must be in perfect health, must have powers of concentration(since work inside a spacecraft is exceptionally demanding)and must have considerable courage. Again, space-work calls for dedication. Courage and dedication are particularly essential. In the well-known case of the Challenger seven crew members lost their lives in space because of the faulty equipment in the shuttle. Another must be outstanding scientific expertise. It goes without saying that they all have to have professional aeronautical qualifications and experience. A striking feature of the astronauts is their ages. For the younger man, in his twenties, say, space is out. Only one of the fifty men working for NASA in 1970 was under 30. The oldest astronaut to date is Alan Shepard, America’s first man in space, who, at nearly fifty, was also the man who captained Apollo 13. The average age is the late thirties. The crew members of Apollo 11 were all born well before the Second World War. In 1986 the Challenger astronauts had an average age of 39. The range was from 35 to 46. In a society where marital continuity is not always exhibited, the astronauts’ record in this respect hits you in the eye. Of all the married men in NASA group, only two or three are divorced from their wives. Mind you, it is hard to tell whether something in the basic character of an astronaut encourages fidelity or whether the selection process demands that a candidate should be happily married. The NASA astronauts live in unattractive small communities dotted here and there around the base in Texas. You would expect them to find their friends from among their professional associates, But this is not the case. Rather, they prefer to make friends with the normal folk in their districts. Astronauts, like everybody else, must get fed up with talking shop all the time, and whereas they are indeed an elite, their daily life outside work should be as normal as possible, if only for the sake of their families. As for the astronauts’ political leanings, they seem to be towards the right. This may be due to the fact that a large proportion of the astronauts have a military background. On the other hand, it could be just coincidence.

What does the man think of the government’ s present proposal about building more power stations in the country?M: Now, I’ d like to say that I think that this government proposing to build more nuclear power stations in this country is really being stupid. The point about nuclear power is that we haven’ t learnt to do away with the waste. We haven’t learnt to cope with the waste from it yet. W: Well, I sometimes think that, you know, they’ ve got an impossible job. I mean all the impression I get is that there is no alternative. . . well, that’ s the impression I get. M: No, no, no I. . . I don’t agree with that at all. There are plenty of alternatives. There’ s the sun. . . solar power. . . that is a source that is always there, we always have it. W: I don’t... I don’t quite see what you’ re getting at actually, solar power, what’ s that? M: Well, the heat from the sun, it can be used in solar panels on the tops of houses for heating, storing up power to heat water and to heat the houses, you know, some solar panels are in operation already and they are saving money... W: That’ s a good point actually, but is it really viable, that, I mean because I’d... M: Sorry it must be! And the one great advantage is that I can see, if the government set up small units to build solar panels and to install them, it would be creating employment which would improve the unemployment situation and bring terrific advantages. W: I have heard that in England, I mean, there’ s not enough sun, is there? For, I mean, solar panels here? M: Yes, well, that’ s not quite true. I. . . there is quite a bit of sun. . . you may not feel the actual heat of it on some occasions. W: No, you are right there! M: But the light power from the sun will. . . It’ s a dangerous proposal. It’ s a stupid proposal. It’ s an advantageous proposal. It’ s a viable proposal.

What do you know about Beethoven’s music talent when he was 7?Beethoven was born in Bonn, Germany, on December 16 or 17, 1770. His father and his grandfather were both musicians. Beethoven exposed his own musical talent when he was very young. His father, an irresponsible drunkard, hoped the boy would be a profitable child prodigy like Mozart. Beethoven was dragged out of bed in the middle of the night and forced to practise the piano. At the age of 7 he was playing in public. When Beethoven was 13, the elector of Cologne made him assistant organist at his chapel in Bonn. In 1787 Beethoven traveled to Vienna and met his idol, Mozart. When Beethoven improvised on a melody that Mozart had given him, the great master was amazed. It is said that Mozart remarked, “This young man will leave his print in the world some day“. But Beethoven could not stay in Vienna. His mother fell ill, and he rushed back to Bonn. The death of his mother left Beethoven and his brothers at the mercy of the drunken father. At the age of 18 Beethoven had to assume full responsibility for the family. In 1792 Beethoven returned to Vienna, where he spent the rest of his life. He became a pupil of Haydn’s but dissatisfied with his method of teaching, which he considered not thorough enough. In order not to offend the famous master, he took lessons in secret from another composer, Johann Schenk. A short, stocky man, untidily dressed, with dark, piercing eyes and a wild shock of black hair, Beethoven presented a strange appearance to the people of Vienna. Knowing himself to be a genius, he lived by his own rules. He refused to bow down to the nobility. He was a man of violent temper and was often rude, even to his closest friends. Goethe, the great German poet, called him an “utterly untamed personality“. Nevertheless, he quickly became well-known. Several princes became his patrons, and for a few years he was happy. Then tragedy struck. He discovered that he was slowly becoming deaf. This was the great crisis of his life. In a letter to his brother, in 1802, Beethoven portrayed his growing deafness and his life loneliness. “ I must live like an exile, “ he wrote, “ I almost put an end to my life. It was only art that withheld me. “ After that Beethoven’s music became profound. He developed a completely original style of composing. It reflected his violent emotions, his sufferings and joys. At this time Beethoven composed the most popular of all symphonies, his fifth. In 1815, Beethoven’s hearing problems steadily increased;by 1820 he was almost totally deaf and had to carry on all conversation in writing. In 1826, Beethoven became seriously ill. It is said that as he lay unconsciously on his deathbed, on March 26, 1827, there was a loud clap of thunder. In response Beethoven sat straight up, shook his fist at the heavens, and fell back dead. Beethoven is perhaps.the most popular and respected of composers. He was a man of profound vision and his music has deeply moved its listeners for generations. In 1970, the 200th anniversary of his birth was celebrated all over the world with a great many performances of his music.

Before a big exam, a sound night’ s sleep will do you better than poring over textbooks. That, at least, is the folk wisdom. And science, in the form of behavioral psychology, supports that wisdom. But such behavioral studies cannot distinguish between two competing theories of why sleep is good for the memory. One says that sleep is when permanent memories form. The other says that they are actually formed during the day, but then “edited“ at night, to flush away what is superfluous. To tell the difference, it is necessary to look into the brain of a sleeping person, and that is hard. But after a decade of painstaking work, a team led by Pierre Maquet at Liege University in Belgium has managed to do it. The particular stage of sleep in which the Belgian group is interested is rapid eye movement(REM)sleep, when brain and body are active, heart rate and blood pressure increase, the eyes move back and forth behind the eyelids as if watching a movie, and brainwave traces resemble those of wakefulness. It is during this period of sleep that people are most likely to relive events of the previous day in dreams. Dr. Maquet used an electronic device called PET to study the brains of people as they practiced a task during the day, and as they slept during the following night. The task required them to press a button as fast as possible, in response to a light coming on in one of six positions. As they learnt how to do this, their response times got faster. What they did not know was that the appearance of the lights sometimes followed a pattern—what is referred to as “ artificial grammar“. Yet the reductions in response time showed that they learnt faster when the pattern was present than when there was not. What is more, those with more to learn(i. e. the “grammar“ , as well as the mechanical task of pushing the button)have more active brains. The “editing“ theory would not predict that, since the number of irrelevant stimuli would be the same in each case. And to eliminate any doubts that the experimental subjects were learning as opposed to unlearning, their response times when they woke up were even quicker than when they went to sleep. The team, therefore, concluded that the nerve connections involved in memory are reinforced through reactivation during REM sleep, particularly if the brain detects an inherent structure in the material being learnt. So now, on the eve of that crucial test, maths students can sleep soundly in the knowledge that what they will remember the next day are the basic rules of algebra and not the incoherent talk from the radio next door.

Some modern cities are usually famous for people who live a very long time.There are several places in the world that are famous for people who live for a very long time. Theses places are usually mountainous areas, far away from modern cities. Doctors, scientists and public health experts often travel to these regions to solve a mysterious long healthy life; the experts hope to bring to the modern world the secrets of longevity. Hunza is high in the Hymalayan Mountains of Asia. There, many people over one hundred years of age are still in physical health. Men of ninety are new fathers, and women of fifty still have babies. What are the reasons for this good health? Scientists believe that the people of Hunza have these three benefits: first, physical work, usually in the fields or with animals; second, a healthy environment with clean air and water; and what’ s more, a simple diet high in vitamins and nutrition but low in fat, cholesterol, sugar and chemicals. People in the Caucasus Mountain in Russia are also famous for their longevity. In this area, there are amazing examples of very long-lived people. Birth records are not usually available, but a woman called Tsurba probably lived until age 160; a man called Shirali probably lived until 168. His widow was 120 years old. In general, people not only live a long time, but they also live well. They are almost never sick, and when they die, they have not only their own teeth but also a full head of hair and good eyesight. Vilcabamba, Ecuador, is another area famous for the longevity of its habitants. This region—like Hunza and the Caucasus—is also in high mountains, far away from cities. In Vilcabamba, too, there is very little disease. One reason for the good health of the people might be the clean, beautiful environment: the temperature is about 70 Fahrenheit all year long; the wind always comes from the same direction; and the region is rich in flowers, fruits, vegetables and wildlife. In some ways, the diets of the habitants in the three regions are quite different. Hunzukuts eat mainly raw vegetables, fruit(especially apricots), and chapattis—a kind of pancake; they eat meat only a few times a year. The Caucasian diet consists mainly of milk, cheese, vegetables, fruit and meat; most people there drink the local red wine daily. In Vilcabamba, people eat a small amount of meat each week, but the diet consists largely of grain, corns, beans, potatoes and fruit. Experts find one surprising fact in the mountains of Ecuador. Most people there, even the very old, consume a lot of coffee, drink a large amount of alcohol, and smoke forty to sixty cigarettes daily. However, the diets are similar in two general ways: first, the fruits and vegetables that the inhabitants of the three areas eat are all natural; that is, they contain no chemicals and second, the people consume fewer calories than people do in the other parts of the world. A typical North American takes in an average of 3, 300 calories every day; a typical inhabitant of these mountainous areas between 1, 700 and 2, 000 calories. Inhabitants in the three regions have more in common calories, natural food, their mountains and their distance from modern cities, because these people live in countryside and are mostly farmers, their lives are physically hard. Thus, they do not need to go to health clubs because they get a lot of exercise in their daily work. In addition, although, their lives are hard, the people do not seem to have the worries of city people. Their lives are quiet. Consequently, some experts believe that physical exercise and freedom from worry might be the two most important secrets of longevity. TRUE FALSE

Psychologists take contrastive views of how external rewards, from【C1】______praise to cold cash, affect motivation and creativity. Behaviorists, 【C2】______research the relation【C3】______actions and their consequences argue that rewards can improve performance at work and school. Cognitive researchers, who study various aspects of mental life, maintain【C4】______rewards often destroy creativity【C5】______encouraging dependence【C6】______approval and gifts from others. The latter view has gained many supporters, especially【C7】______educators. But the careful use of small monetary rewards sparks【C8】______in grade-school children, suggesting【C9】______properly presented inducements indeed aid inventiveness, 【C10】______to a study in the June Journal of Personality and Social Psychology. “If kids know they’re working for a【C11】______and can focus【C12】______a relatively challenging task, they show the most creativity“ , says Robert Eisenberger of the University of Delaware in Newark. “But it’s easy to kill creativity by giving rewards for【C13】______performance or creating too【C14】______anticipation for rewards. “ A teacher【C15】______continually draws attention to rewards or who hands【C16】______high grades for ordinary achievement ends up【C17】______discouraged students, Eisenberger holds.【C18】______an example of the latter point, he notes growing efforts at major universities to tighten grading standards and restore failing【C19】______. In earlier grades, the use of so-called token economies, in【C20】______students handle challenging problems and receive performance-based points toward valued rewards, shows promise in raising effort and creativity, the Delaware psychologist claims.

As international commerce grows, there is an amazing development which is expanding at ever-increasing rate—business on the Internet. One of the most arresting auction business is called e-Bay. Down at the local auction house in the city, you would normally find excited bidders raising their hands or nodding agreement as the auctioneer rattles off the prices for a set of bookshelves, heater or second-hand television set. Now the same cut and thrust of auction selling is drawing not the hundreds who cram into a crowded auction room, but millions of Internet surfers who visit e-Bay, the biggest online auction site, and others of similar style. 【R1】______ For example, in one month when I looked at the colorful e-Bay site, these were numbers of items for sale in some of the major categories: Collectibles 684, 473; Sports Memorabilia 269, 051; Books, Movies, Music 267, 324; Toys 242, 155; 【R2】______ According to the e-Bay promotion, users can find the unique and the interesting on e-Bay—everything from chintz china to chairs, teddy bears to trains, and furniture to figurines. So why do people come to e-Bay? As the leading person-to-person trading site, Buyers trade on e-Bay because of the great number of items available. If you want it, somebody’s probably selling it on e-Bay. Similarly, sellers are attracted to e-Bay to conduct business because e-Bay has the most buyers. There are over a million auctions happening on e-Bay every day. 【R3】______ “ People tell us that they come for all the cool stuff they can get, But they stay, even after they finish their collection , for the fun people they meet at e-Bay. ’ Take your time, and get to know the e-Bay world’ is their advice. So how do you make a bid and buy something at this auction? 【R4】______ First I had to register my name, email address and password with e-Bay. So they can track the sales and make sure that everybody is fair dealing. Remembering that bidding online is the same as buying or entering a contract with the seller, I searched under guitars in the Musical Instruments section with my mouse clicking on the various pages. I had a good look at the seller’s feedback record. If the person selling goods on e-Bay has tried to cheat, or back out of a deal, email users of e-Bay can leave their own feedback comments, praising or criticizing the e-Bay seller, or bidder. This is everyone can see what is going on. The e-Bay company can ban anyone who has not acted by the rules. 【R5】______ The auction details were set out and the day the auction was to end(in one week’s time). There was a nice picture of the guitar. I reviewed my bid of $20 to ensure that all the information was correct and clicked on the button “ Place Bid“. Unfortunately I was notified that my bid was not the highest—someone else had bid more money, so I missed out. However, if I had put in the highest bid, the e-Bay website would have notified me that I was the highest bidder for the time being. When the auction ends, the highest bidder buys the goods. A. Among the special items for sale are an illustration of the winners from 84 Years of the USA Open Golf tournament, signed by the famous golfers, and framed. There is a Beatles Original Coin, especially minted for the first US tour in 1964 of the famous Liverpool pop music group. Furniture, new kitchen knives, guitar study programs, computers—you name it e-Bay auction site has it, as people world-wide take advantage of the chance to sell their goods to the biggest market in the world—the cyberspace community of Internet watchers. B. This is a business that allows customers to buy and sell goods by offering them for sale, or bidding for items displayed at the e-Bay website, as if they were at an auction. Currently, e-Bay has listed at its website 2.14 million items for sale in 1, 627 categories. Each month the e-Bay site has 1.5 billion visitors who view the e-Bay pages, looking for bargains or working out how much to charge for that bed or unwanted TV they want to list for auction. C. I was looking for a guitar and this is what I did. D. There are not many stores in the world where they praise you as a good shopper or give you minus points in public if you are a bad customer. But this is the kingdom of the Internet where the rules are being constructed as the system develops. E. According to an e-Bay spokesperson, e-Bay is more than just a place to trade. It’s also a place to meet that one other person in the world who shares your passion for your own particular interest, whether it’s stamps, war memorabilia, sporting goods, furniture or computer programs, for example. F. Then I was ready to bid. It does not cost any money to bid on items at e-Bay. Of course, if you win the auction, you must pay the seller directly, But you will not be charged anything by e-Bay.

A = Hydro power B = Nuclear power C = Solar power D = Wind power Which power(power’ s)... was developed to provide electricity for satellites at the beginning? 【P1】______ can promote tourism development? 【P2】______ may give off dangerous radioactive pollution into the air? 【P3】______ may affect the downstream water quality and have an impact on plant life? 【P4】______ stations can increase to full power very quickly? 【P5】______ produces small amounts of waste? 【P6】______ is a good method of supplying energy to remote areas? 【P7】______ provides around 20% of the world’ s electricity? 【P8】______ can be used to heat your water at home instead of so much gas or electricity? 【P9】______ is not renewable? 【P10】______ A Hydro power Introduction We have used running water as an energy source for thousands of years, mainly to grind corn. The first house in the world to be lit by hydroelectricity was Cragside House, in Northumberland, England, in 1878. In 1882 on the Fox River, in the USA, hydroelectricity produced enough power to light two paper mills and a house. Nowadays there are many hydro-electric power stations, providing around 20% of the world’ s electricity. The name comes from “hydro“ , the Greek word for water. How it works A dam is built to trap water, usually in a valley where there is an existing lake. Water is allowed to flow through tunnels in the dam, to turn turbines and thus drive generators. Advantages Once the dam is built, the energy is virtually free. No waste or pollution produced. Much more reliable than wind, solar or wave power. Water can be stored above the dam ready to cope with peaks in demand. Hydro-electric power stations can increase to full power very quickly, unlike other power stations. Disadvantages The dams are very expensive to build. Building a large dam will flood a very large area upstream, causing problems for animals that used to live there. Finding a suitable site can be difficult—the impact on residents and the environment may be unacceptable. Water quality and quantity downstream can be affected, which can have an impact on plant life. Is it renewable? Hydro-electric power is renewable. The Sun provides the water by evaporation from the sea, and will keep on doing so. B Nuclear power Introduction Nuclear power is generated using Uranium, which is a metal mined in various parts of the world. The first large-scale nuclear power station opened at Calder Hall in Cambria, England, in 1956. Some military ships and submarines have nuclear power plants for engines. How it works Nuclear power stations work in pretty much the same way as fossil fuel-burning stations, except that a “chain reaction“ inside a nuclear reactor makes the heat instead. The reactor uses Uranium rods as fuel, and the heat is generated by nuclear fission. Neutrons smash into the nucleus of the uranium atoms, which split roughly in half and release energy in the form of heat. Carbon dioxide gas is pumped through the reactor to take the heat away, and the hot gas then heats water to make steam. Advantages Nuclear power costs about the same as coal, so it’ s not expensive to make. Does not produce smoke or carbon dioxide, so it does not contribute to the greenhouse effect. Produces huge amounts of energy from small amounts of fuel. Produces small amounts of waste. Disadvantages Although not much waste is produced, it is very, very dangerous. It must be sealed up and buried for many years to allow the radioactivity to die away. Nuclear power is reliable, but a lot of money has to be spent on safety. Is it renewable? Nuclear energy from Uranium is not renewable. Once we’ ve dug up all the Earth’ s uranium and used it, there isn’ t any more. C Solar power Introduction We’ ve used the Sun for drying clothes and food for thousands of years, but only recently have we been able to use it for generating power. The Sun is 150 million kilometers away, and amazingly powerful. Just the tiny fraction of the Sun’ s energy that hits the Earth(around a hundredth of a millionth of a percent)is enough to meet all our power needs many times over. How it works There are three main ways that we use the Sun’ s energy: Solar Cells(really called “photovoltaic“ or “photoelectric“ cells)that convert light directly into electricity. In a sunny climate, you can get enough power to run a 100W light bulb from just one square meter of solar panel. This was originally developed in order to provide electricity for satellites, but these days many of us own calculators powered by solar cells. Solar water heating, where heat from the Sun is used to heat water in glass panels on your roof. This means you don’t need to use so much gas or electricity to heat your water at home. Solar Furnaces use a huge array of mirrors to concentrate the Sun’ s energy into a small space and produce very high temperatures. Advantages Solar energy is free—it needs no fuel and produces no waste or pollution. In sunny countries, solar power can be used where there is no easy way to get electricity to a remote place. Handy for low-power uses such as solar powered garden lights and battery chargers. Disadvantages Doesn’ t work at night. Very expensive to build solar power stations. Solar cells cost a great deal compared to the amount of electricity they’ 11 produce in their lifetime. Can be unreliable unless you’ re in a very sunny climate. Is it renewable? Solar power is renewable. The Sun will keep on shining anyway, so it makes sense to use it. D Wind power Introduction We’ ve used the wind as an energy source for a long time. The Babylonians and Chinese were using wind power to pump water for irrigating crops 4, 000 years ago, and sailing boats were around long before that. Wind power was used in the Middle Ages, in Europe, to grind corn, which is where the term “windmill“ comes from. How it works The Sun heats our atmosphere unevenly, so some patches become warmer than others. These warm patches of air rise, other air blows in to replace them—and we feel a wind blowing. We can use the energy in the wind by building a tall tower, with a large propeller on the top. The wind blows the propeller round, which turns a generator to produce electricity. The more towers, the more wind, and the larger the propellers, the more electricity we can make. Advantages Wind is free, wind farms need no fuel. Produces no waste or greenhouse gases. The land beneath can usually still be used for farming. Wind farms can be tourist attractions. A good method of supplying energy to remote areas. Disadvantages The wind is not always predictable—some days have no wind. Suitable areas for wind farms are often near the coast, where land is expensive. Can kill birds—migrating flocks tend to like strong winds. Can affect television reception if you live nearby. Is it renewable? Wind power is renewable. Winds will keep on blowing; it makes sense to use them.

For many university students there are two alternatives: one is to find a job, the other is to pursue further study. Both have advantages and disadvantages, and it is difficult to say which is better. Which choice is more suitable for you!

Researchers in behavioral psychology are divided with regard to______.

As manifested in the experimental study, rapid eye movement is characterized by______.

By referring to the artificial grammar, the author intends to show______.

In their study, researchers led by Pierre Maquet took advantage of the technique of______.

What advice might Maquet give to those who have a crucial test the next day?