1·Dark clouds massed on the horizon.
天边乌云密布。
—— 《牛津词典》
2·There were dark clouds overhead promising rain.
天上乌云密布，预示就要下雨。
—— 《牛津词典》
3·Lightning flashed among the distant dark clouds.
远处的乌云中电光闪闪。
—— 《柯林斯英汉双解大词典》
4·The dark clouds in the sky meant that a storm was coming.
天空中的乌云预示暴风雨即将来临。
—— 《牛津词典》
5·The sky is overcast with dark clouds.
乌云满天。
—— 《新英汉大辞典》
6·Dark clouds means rain.
乌云意味着要下雨。
7·The moon was covered by the dark clouds.
月亮被乌云遮住了。
8·Suspended on their stilts, the actors remove their masks and reveal their off-white faces, staring terrified at a sunless sky, dark clouds congregating.
演员们被吊在高跷上，他们摘下面具，露出他们苍白的脸，惊恐地盯着没有阳光，乌云聚集在一起的天空。
9·There were ominous dark clouds gathering overhead.
不祥的阴霾在头顶上汇聚。
—— 《牛津词典》
10·The dark clouds threatened a big storm.
乌云预示暴风雨的来临。
—— 《新英汉大辞典》