cloud over
phrasal verb with cloud verb uk/klaʊd/ us/klaʊd/
(SKY)
阴云密布，乌云翻滚
If the sky clouds over, it becomes covered with clouds.
(FACE)
（脸色）阴沉;愁云满面;忧郁
If a person's face clouds over, they suddenly look unhappy or worried.
At the mention of her dead husband, her face clouded over. 一提到死去的丈夫，她的脸色就阴沉下来。