出版时间:2009-8 出版社:群言出版社 作者:哈尔,米尔奇,麦考马克 页数:350 译者:蔡青,刘洋
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内容概要
《新托福考试专项进阶》系列丛书从托福考试所考查的听、说、读、写四项技能人手,为考生提供了详尽的考试指导,并将各技能分为初、中、高三级,逯过独特的“进阶训练”方式,再辅以大量练习,让考生逐步掌握托福实考的技巧,同时切实提高英语实际运用能力,从而在短期内轻松取得托福高分。本丛书内容编排由易到难,循序渐进,实战性强,是不可多得的托福备考资料。 本丛书引进自韩国多乐园出版社。该社成立于1977年,在韩国英语教育出版领域始终处于领军地位。本丛书被韩国众多学校和培训机构指定为课堂教材,在托福考生中享有较高声誉。
书籍目录
Contents PART 1 Basic Comprehension Unit 1 Vocabulary Biology/Sociology|Literature Unit 2 Reference Science|History|Economics Unit 3 FactuaIInformation Art/Geography|Politics Unit 4 Negative Factual Information Culture/Astronomy/Chemistry Unit 5 Sentence Simplification Ecology/Biology/Geology PART 2 Making Inferences Unit 6 RhetorlcaI Purpoae Zoology/Sociology/Literature|Language Unit 7 Inference Psychology/History/Geography Unit 8 lnsertText Art/Economics/Science PART 3 Reading to Learn Unit 9 Prose Summary Geology/Astronomy/Chemistry Unit l0 Fill in aTable Culture/Anthropology/Ecology|Biology Vocabulary Wrap-up ActuaITest 01 ActuaITest 02Contents(Answer Book) Unit 1 Vocabulary Unit 2 Reference Unit 3 Factual Information Unit 4 Negative Factual Information Unit 5 Sentence Simplification Unit 6 Rhetorical Purpose Unit 7 Inference Unit 8 InsertText Unit 9 Prose Summary Unit 10 Fill in a Table Actual Test 01 Actual Test 02
章节摘录
The principles making radio possible were developed throughout the nineteenth century. The first breakthrough was by the British physicist Michael Faraday in 1831. He discovered that when an electric current passes through one wire, it produces a current in another wire even though the wires do not touch each other. In 1864, James Maxwell showed that this current——composed of electromagnetic waves——travels at the speed of light. Heinrich Hertz proved that the waves pass through solid objects. With these discoveries in place, the race was on to develop a system of wireless radio. Among the contenders was Reginald Fessenden, a Canadian inventor. Fessenden began experimenting with radio detectors in order to explore the possibility of voice transmission. In 1900, he was the first person to transmit his voice, but the sound was unrecognizable because the waves were not continuous. He invented a barreter detector, taking its name from the French word exchanger, to receive AM (amplitude modulated) signals, but it was not sensitive enough. One day in 1901, he accidentally left a filament of wire in acid for too long until only a tip of the wire was in contact with the acid. Fessenden noticed that, with the wire in the acid, the barreter was very sensitive to nearby continuous radio waves. Fessenden called his invention a liquid barreter, but it became known as an electrolytic detector. The detector consisted of several connected parts forming an electric circuit. A silver-coated platinum wire was dipped into a small platinum cup filled with nitric or sulfuric acid and connected to the ground. A battery was connected between the wire and the acid, prompting a current to flow in the detector. Someone wearing headphones that were hooked up to the detector could hear a hissing noise, which could be adjusted by turning a dial until the hissing noise stopped. At that point, the detector was highly sensitive to incoming radio waves.
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