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新东方优美背诵短文50篇 Unit35:Oil Refining 35.Oil Refining An important new industry, oil refining, grew after the Civil war. Crude oil, or petroleum – a dark, thick ooze from the earth – had been known for hundreds of years, but little use had ever been made of it. In the 1850’s Samuel M. Kier, a manufacturer in western Pennsylvania, began collecting the o...