【淘金专四听写】020 用种子榨油

英语自学网

2012淘金英语专业四级听写      
上海外国语大学
请从正文部分开始听写Oil is separated from seeds by using pressure. A machine called a press is often used. The first step in pressing the oil from seeds is to crush the seeds between two stones. A cloth container or bag is filled with the crushed seeds. Then the bag is hung up. Some of the oil will flow out of the bag and can be collected. But some oil will remain in the crushed seeds inside the bag. The easiest way to get the rest of the oil out is to place heavy rocks on the crushed material. Another method is to place several cloth bags on top of each other in a box. Then a long wooden stick is used to slowly push a heavy cover down on the bags. Great pressure is produced in this way. Much greater pressure can be produced by using a machine. The greater the pressure,
the more oil will be produced.