新東方·新托福考試專項進階:高級閱讀 epub pdf mobi txt 電子書 下載 2024
發表於2024-09-19
新東方·新托福考試專項進階:高級閱讀 epub pdf mobi txt 電子書 下載 2024
Timothy Hall,畢業於美國哥倫比亞大學,英語語言學專業碩士。
Arthur H. Milch,美國新澤西學院TESOL專業教育學碩士。
Denise McCormack,美國新澤西學院TESOL專業教育學碩士。
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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新東方·新托福考試專項進階:高級閱讀 epub pdf mobi txt 電子書 下載 2024
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評分美國的大學在錄取工作中越來越看重托福成績,尤其在2012年不少美國大學提高瞭對國際生的托福錄取標準,托福錄取分數綫上調幅度大概在10分左右,比如凱斯西儲大學(Top38)由2011年的80分上調至2012年的90分。俄亥俄州立大學由2011年的71分上調至2012年的79分。這一現象在高端名校中更為嚴重,綜閤排名Top20的埃默裏大學甚至建議學生考取托福100分以上。中國大學生去紐約、倫敦、香港的大學留學,托福成績都是被申請學校認可的。因此到紐倫港留學考托福成績的占絕大部分。[2]
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評分新東方·新托福考試專項進階:高級閱讀 epub pdf mobi txt 電子書 下載 2024