常用于形容下雨下得大。
以下是网站上的解释:
cats and dogs
n. 价值低的股票, 不值钱的.卖不掉的商品
例句与用法:
In the middle of the picnic it started to rain cats and dogs, and we all got soaked.
正野餐时开始下起了倾盆大雨,大家全身都湿透了。
In the middle of the picnic it started to rain cats and dogs, and everyone got soaked.
野餐进行到一半时,下起了倾盘大雨,大家都被子淋得湿透了。
Cats and dogs have quite different natures dogs like company, cats are independent.
猫和狗的习性迥异--狗喜欢有伴,猫爱独来独往。
It's raining cats and dogs outside.
外面正下着倾盆大雨。
参考资料:http://dict.cn/cats-and-dogs.htm