n.百万吨级；兆吨
Inspite of the various difficulties,Chengdao was develoed independantly into a megaton oilfield in a period as short as a few years. 工程设计完全依靠自己的力量，克服了种种困难，在短短的几年内就将埕岛建设成为一个百万吨级的油田。
