n.套；罩；匣；盒；[经](石油)套管；包装
动词case的现在分词.
An oxygen mask will come down from overhead in case of an emergency. 若发生紧急情况，头顶上会降下一只氧气面罩。
A decorative casing for a light, often of paper. 灯笼灯的装饰性外套，经常用纸制成
Such a projectile in a metal casing; a cartridge. 弹药(筒)装在金属盒中的射弹。弹药
套管
n.砌面(外壳；装入)
