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The author expressed his regret to his friend and his wife for arriving there too late.
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With Airbus's giant A380 airliner about in to take to the skies, you might think planes could not get much bigger — and you would be right. For a given design, it turns【21】, there comes a point where the wings become too heavy to generate【22】lift to carry their own weight.【23】a new way of designing and making materials could【24】that problem. Two engineers【25】University College London have devised an innovative way to customise and control the【26】of a material throughout its three-dimensional structure.
In the【27】of a wing, this would make possible a material that is dense, strong and load-bearing at one end, close to the fuselage,【28】the extremities could be made less dense, lighter and more【29】. It is like making bespoke materials,【30】you can customise the physical properties of every cubic millimetre of a structure.
The new technique combines existing technologies in a(n)【31】way. It starts by using finite-element-analysis software, of the type commonly used by engineers,【32】a virtual prototype of the object. The software models the stresses and strains that the object will need to【33】throughout its structure. Using this information it is then【34】to calculate the precise forces acting on millions of smaller subsections of the structure.【35】of these subsections is【36】treated as a separate object with its own set of forces acting on it — and each subsection【37】for a different microstructure to absorb those local forces.
Designing so many microstructures manually【38】be a huge task, so the researchers apply an optimisation program, called a genetic algorithm,【39】This uses a process of randomization and trial-and-error to search the vast number of possible microstructures to find the most【40】design for each subsection.
(1)
听力原文：M: Please come in, Miss Edwards, and close the door behind you.
W: All right. What do you want me to do, Mr. Davis？
M: Have a ,seat over there. How are things going in the office？
W: Just fine, Mr. Davis, especially with recent personnel shifts.
M: Yes, I thought so. Well, I and the executive board feel that much of your improved performance in the main office is due to your conscientious efforts.
W: Oh, thank you, Mr. Davis. My job has certainly become easier since we computerized our record-keeping system. The equipment is convenient to use.
M: That's true. But we are especially impressed with how your influence contributes to good office relations and improved staff attitude toward the work.
W: Well, thank you for your confidence in me. We do have a lot of good people in the office, and the new machinery is wonderful.
M: Yes, but machines are only as good as the people who use them. They can't ensure harmony and efficiency in a staff.
W: That's very true.
M: To make a long story short, the board wishes to reward your efforts by making you office manager as of next Monday. That means a $ 250 raise as of the first of next month.
W: I'm deeply honored, Mr. Davis. Thank you.
(23)
A．north and south.B．east and west.C．south and west.D．north and east.
听力原文： England became a stronghold of the Protestant version of Christianity during the 16th Century. In thel7th century, the British people developed a system of government by parliament which was later copied in many other countries. During the18th Century, the great revolutions in farming and industry that later took place worldwide, began in Britain. Steam power, steam trains, coal mines and water power began to transform. the means of transport and production. The world's, first industrial cities grew in the Midlands. Then, in thel9th Century, the development of a massive British Empire brought power and wealth to the nation. By the time Queen Victoria took the throne in 1837, Britain had be come the world's greatest power.
Later on, in the 20th century, Britain played a vital part in saving Europe from the threat of Fascism during World War Two.
In1966, England won the Football World Cup and became World Champion. This is some thing many British people are very proud of.
Britain joined the European Community in 1973, but was still separated from mainland Europe. Finally, in 1994 the Channel Tunnel was opened, which links Britain back to the European continent.
The first men and women came to Britain over two and a half million years ago. They were hunters and gatherers of food who used simple stone tools and weapons.
Britain used to be joined to, the European land mass. It became an island separate from the rest of Europe about 8,500 years ago, when melting ice formed the English Channel.
Britain has been invaded by people from Italy, Germany, Scandinavia and France, each bringing with them their own languages and customs.
(30)
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