这就是所谓的催化裂化.It is known as catalytic cracking.裂化是使较重的低挥发性的碳氢化合物分裂成较小分子的化学分裂.Cracking involves the chemical breakdown of higher, less volatile hydrocarbons into smaller molecules.FCC(流化催化裂化 ) 是炼厂生产汽油的主要方法之一.The Fluid Catal...
She has taken an active part in all past contests.她积极参加历次比赛.The amphitheater was a sealed off round structure . Swordplay, wresting, gladiatoral and other contests were held there.该竞技场为四周封闭式结构,可以举行斗剑 、 格斗 、 斗兽及其他竞赛项目.The...