请问一下，虚拟语气要退格时态的有哪些

Answer 1

虚拟语气中时态倒退一个的对应用于以下情况：
1、非真实条件句中：
①与现在事实相反，If条件从句中谓语用过去时态，主句中用would (should等)＋动词原形，如：If I were you, I would give her some help now.
②与过去事实相反，If条件从句用过去完成时态had＋-ed分词，主句中用would(should等)＋have＋ed分词，如：
If it hadn't been for your help, we would have failed then.
2、在wish后面的宾语从句，表示对现在的希望，从句中谓语动词用过去时态，如：
I wish I knew the answer now.
表示对过去的希望，从句中谓语动词用had＋过去分词，如：
I wish that he had gone there.
If only引起的感叹句，其形式和意义同wish
3、在as if / though引起的方式状语从句或表语从句中用虚拟语气时，谓语形式同wish用法，如：They are talking as they had known each other many years ago.
4、在would rather后面的从句中对现在的虚拟“希望”，从句中动词用过去时态；用过去完成式虚拟过去的情况，如：I would rather I had seen the film.