It ( )impossible for us to meet again without the help of the polecemen.为啥选would have been?为何不是would be.为啥这是对过去事实相反的一种假设,而不是现在?

It ( )impossible for us to meet again without the help of the polecemen.为啥选would have been?
为何不是would be.为啥这是对过去事实相反的一种假设,而不是现在?

would have done/been 是虚拟语气,表示过去本会是这种结局,结果事实上却是另一种.翻译过来是,没有警察的帮助,我们本不可能在见面了.