雾很大英语怎么说

"Fog is heavy" 英文说法是 "The fog is dense."。

雾是由水汽冷凝形成的天气现象，密度越大，就表示雾很浓厚。

一些例句：

"The dense fog made it difficult to see the road ahead." (浓雾使前方的路难以看清)
"Visibility was severely limited due to the heavy fog." (因为浓雾，能见度严重受限)
"The dense fog blanketed the city, creating a mystical atmosphere." (浓雾笼罩了整座城市，制造了一种神秘的气氛)