black cloud

基本解释

You see this dark black cloud hovering over the surface of Earth?
能看见这盘旋在地表的深黑色的云吗？
While I knew I shouldn’t let it, the mailman’s morning delivery of another rejection letter for an article I’d submitted to a magazine made me feel like a black cloud of failure hung over my head.
虽然我知道自己不该这样，但是早班邮差送来的又一封我给杂志投稿的退稿信就象是一片失败的乌云挂在我的头顶上。
From the plane, you could see the vast black smoke-cloud that used to be Japan's biggest oil refinery, still burning unstoppably 24 hours after the earthquake hit it.
从飞机上鸟瞰，你可以看到从日本这个曾经最大的炼油厂内冒出的滚滚浓烟，在地震发生后的24小时里厂内的大火一直没有停止过燃烧。

Another longer-term structural black cloud looming over the U.S. Treasury market remains the huge budget deficit.
FORBES: Fed Watch 2012: What Does Ben Have Up His Sleeve Now?
For some investors, the stock market has a permanent black cloud over it.
FORBES: Greed is Good; Fear is Better
The black cloud is that a war which has already killed about 55, 000 people, soldiers and civilians together, shows no signs of ending.
ECONOMIST: Sri Lanka