题目内容
SECTION B PASSAGES
Directions: In this section, you will hear several passages. Listen to the passages carefully and then answer the questions that follow.
听力原文： In ancient times, many people believed the earth was a flat disc. Well over 2,000 years ago, the ancient Greek philosophers were able to put forward two good arguments proving that it was not. Direct observation Of heavenly bodies was the basis of both these arguments. First, the Greeks knew that during eclipses of the moon, the earth was between the sun and the moon, and they saw that during these eclipses, the earth's shadow on the moon was always round, they realized that this could be true only if the earth was spherical. If the earth were a flat disc, then its shadow during eclipses would not be a perfect circle, it would be stretched out into a long ellipse. The second argument was based on what the Greeks saw during their travels. They noticed that the North Star, or Polaris, appeared lower in the sky when they traveled south, in more northerly regions, the North Star appeared to them to be much higher in the sky. By the way, it was also from this difference in the apparent position of the North Star that the Greeks first calculated the approximate distance around the circumference of the earth, a figure recorded in ancient documents says 400,000 stadia, that's the plural of the word stadium. Today, it's not known exactly what length one stadium represents, but let's say it was about 200 meters, the length of many athletic stadiums. This would make the Greek's estimate about twice the figure accepted today, a very good estimate for those writing so long before even the fast telescope was invented.
According to the professor, what were, the beliefs of the Greek philosophers based upon？
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听力原文： Let's turn our locus now to advertising. We all know what an advertisement is. It's essentially a message that announces something for sale. Now, there is an important precondition that must exist before you have advertising, and that's a large supply of consumer goods, that is, things to sell. You see, in the place with a demand for a product is greater than the supply, there's no need to advertise. Now, the early form. of advertising going back many hundreds of years with a simple sign there were shop doors that told you whether the shop was a bakery, a butcher shop or what have you, then was the advent of the printing crest. Advertising increased substantially as for products like coffee, tea, and chocolate appeared in newspapers and another periodicals as well as on the side of the buildings. In the American colonies, advertising in communication's media like newspapers and pamphlets became a major factor in marketing goods and services. By modern standards, these early advertisements were quite small and subdue, not the splash sheet whole page spreads of today, still some of them appeared on the front page of newspapers, probably because the news often consist of less and fresh reports from distant Europe, for the ads were current or local. Advertising really came into its own and became a central part of doing business, during the industrial revolution, suddenly there was a much greater supply of things to sell. And as we said earlier, that is the driving force behind advertising. People's attention had been drawn to the new product. Let's take a look at some of the advertisements from that time.
What is the main topic of the passage？
正态分布的概率密度函数，总体标准差一愈大，曲线低而宽，随机变量在平均值μ附近出现的密度愈小；总体标准差σ愈小，曲线高而窄，随机变量在平均值μ附近出现的密度愈大。()
The Internet can make the news more democratic, giving the public a chance to ask questions and seek【C1】______facts behind stories and candidates, according【C2】______the head of the largest US on-line services.
"But the greatest【C3】______for public participation is still in the future," Steven Case, Chairman of America On-line, told a recent meeting on Journalism and the Internet【C4】______mainly by the Freedom Forum.【C5】______, stone other experts often say the new technology of computers is【C6】______the face of journalism, giving reporters【C7】______to more information and their readers a chance to ask questions and turn to【C8】______sources.
"You don't have to buy a newspaper and be【C9】______to the four comers of that paper any more", Sam Meddis, on-line technology editor at USA Today,【C10】______about the variety of information【C11】______to computer users.
But the experts【C12】______the easy access to the Internet also【C13】______anyone can post information for others to sec. "Anyone can say anything they want,【C14】______it's right or wrong," said Case. Readers have to【C15】______for themselves whom to trust. "In a world of almost【C16】______voices respected journalists and respected brand names will【C17】______become more important, not less," Case said.
The Internet today is about【C18】______radio was 80 years ago, or television 50 years ago or cable 25 years ago, he said. But it is growing rapidly【C19】______it provides people fast access to news and a chance to【C20】______on it.
【C1】
A．Mental addiction.B．Substance independence.C．The desired effects.D．Substance dependen
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