Above 5,490m is the realm of the heavy jets, since jet engines operate more efficiently at higher altitudes.
超过5490米是重型喷气式飞机的领域，因为喷气式发动机在更高的高度运行时效率更高。
2
The boards of directors, all of which are still Brit-heavy, would have to be rejigged—unless board meetings were to become jet-lag experiments.
董事会已大部分英国化，需要重新调整，除非要将董事会议当作时差综合症实验。
3
The paper describes the feature, mechanism of formation, research methods and possible applications of jet halo of mobile heavy metal above oil bearing formation.