长期下雨用英语怎么说

"长期下雨" 用英文可以表示为 "it has been raining for a long time" 或 "there has been a long period of rain."

这个表达方法来自于英语中常用的一种表达方式，即使用现在完成时态来表示过去发生的持续性动作或状态。现在完成时态由助动词 "have" 和过去分词 "been" 组成，意思是 "已经" 或 "之前已经"。

下面是一些例句：

It has been raining for a week. (已经下雨一周了。)
There has been a long period of rain in the forecast. (预报中有长期的雨水。)
It has been raining nonstop since yesterday. (自从昨天以来就一直在下雨。)

希望这些例句对您有帮助。