Gb	Eng
乌云预示着暴风雨的到来。	The clouds presage a storm.
乌云密布预示着将要下雨。	The black clouds threatened rain.
乌云是雨或雪将至的预兆。	Dark clouds are a sign of rain or snow.
乌云是下雨的明显前兆。	Black clouds are an unmistakable sign of coming rain.