storm-cloud
n
(a) large black cloud coming with a storm or indicating that a storm is likely to happen 暴风云(暴风雨时出现的或预示暴风雨将至的浓密的乌云).
(b) (usu pl 通常作复数) (fig 比喻) sign of sth dangerousor threatening 危险的迹象; 凶兆
storm-clouds of war gathering over Europe 笼罩著欧洲上空的战争乌云.