It's rain cats and dogs.意义

It's rain cats and dogs.意义 It rain cats and dogs. it`s raining cats and dogs now .the words "rain cats and dog rain cats and dogs "Rain cats and dogs'' rain dogs and cats It's raining cats and dogs It's raining cats and dogs outside 英语翻译It's raining cats and dogs It's raining cats and dogs 英译汉 根据汉语提示完成句子 It's＿＿（rain）cats and dogs outside. rain cats and dogs是什么意思?