这题是不是要把句子改成虚拟语气啊?怎么改

题目

这题是不是要把句子改成虚拟语气啊?怎么改
2、We allowed the oil company to build this paper mill.Therefore,we have water pollution now.(change it to indicate something unreal)

答案

是改成虚拟
改：
We should have allowed the oil company to build this paper mill.therefore,we would not have water pollution now.
前面一句是对过去的虚拟,用should have done；后面一句是对现在的虚拟,用would do.should和would的选择是根据句意的,前句是“应该”,后句是“能够”.