一、与现在事实相反的虚拟语气
条件句 - 结构：
If + 主语 + 过去时，主语 + should （could/would/might） + 动词原形
- 例句：
- If I were you, I would study hard.
- It is high time you were in bed.
表语从句/方式状语从句 - 结构：
主语 + look/talk/act + as if/though + 过去分词/动词过去式
- 例句：
- She looks as if she were very ill.
- He talks as if he had been on the spot.
二、与过去事实相反的虚拟语气
条件句 - 结构：
If + 主语 + had + 过去分词，主语 + should （could/would/might） + have + 过去分词
- 例句：
- If the doctor had come last night, the boy would have been saved.
- If I had studied hard, I would have passed the exam.
表语从句/方式状语从句 - 结构：
主语 + 动词过去式 + as if/though + 主语 + had + 过去分词
- 例句：
- She acted as if I were her servant.
- He spoke as if he had known the news.
三、与将来事实相反的虚拟语气
条件句 - 结构：
- If + 主语 + 过去时/should + 动词原形，主语 + should （could/would/might） + 动词原形
- If + 主语 + were to + 动词原形，主语 + should （could/would/might） + 动词原形
- 例句：
- If it should rain tomorrow, we would stay at home.
- If I were to travel the world, I would learn to speak six languages.
表语从句/方式状语从句 - 结构：
- 主语 + 动词过去分词/should + 动词原形（表示对将来的虚拟）
- 例句：
- The situation seems as if it would be out of control.
四、含蓄虚拟语气（特殊结构）
as if/though + 从句 - 结构：
与现在/过去/将来事实相反，从句谓语用过去式/过去完成式/would + 动词原形
- 例句：
- The letter arrived as if it were yesterday.
- The meeting started as though we had already discussed the plan.
五、其他常见结构
would rather + 从句 - 结构：
表示现在愿望用过去式，表示过去愿望用had + 过去分词，表示将来愿望用would + 动词原形
- 例句：
- I would rather she were not here.
- I wish I had not wasted so much time.
It is high time that + 从句 - 结构：
虚拟语气，从句用过去时/should + 动词原形
- 例句：
- It is high time that you children went to bed.
以上句型覆盖了虚拟语气的主要用法，通过不同结构表达与现在、过去、将来事实相反的假设，以及含蓄表达愿望等特殊场景。
