1)primary recovery efficiency,一次采油采收率2)primary recovery factor,一次采油采收率3)once,一次4)bout,一次5)PRY Primary,一次6)at a time,一次7)primary air,一次风，一次空气8)over and over (again),一次又一次;反复9)primary purification,一次精制10)one weighting,一次加重
用法例句
This study was carried on the primary purification of sodium chloride from flotation salt in potassium chloride production in Qinghai salt industrial company.
