If the weather had been better ,we could have had the concert in the openb air,But it_all day

问题描述:

If the weather had been better ,we could have had the concert in the openb air,But it_all day
A rains B rained C has rained Dis raining
想问一下为什么用B不用C C不是也能表示过去而且已经完成了 这个下雨不是已经下了一整天的意思吗?

前面是对过去情况的一种假设,(即虚拟),表明这是过去发生.