翻译请帮忙? When the crude oil is obtained from the field,it is taken to the refineries to be treated. The commonest form of treatment is heating. When the oil is heated,the first vapors to rise are cooled and become the finest petrol. Petrol has a low boiling point; if a little is poured into the hand,it soon vaporizes. Gas that comes off the oil later is condensed into paraffin. Last of all the lubricating oils of various grades are produced. What remains is heavy oil that is used as fuel. 查看更多4个回答 . 4人已关注