It has been snowy for two days为什么不用snowing

用It has been snowing for two days. 也是正确的,意思有点变化.译为：一直下了两天雪了.（此时还在下）那就是It has been snowy for two days是对得咯为什么啊、?????????????????因为snowy是形容词，可以表示（下雪）状态持续了2天。所以都是正确的。