Y0086虚拟语气
以下是三种虚拟语气（与现在事实相反、与过去事实相反、与将来事实相反）的语法总结表格，包含结构、例句及关键说明：
| 虚拟语气类型 | 条件从句结构 | 主句结构 | 例句 | 关键说明 |
|---|---|---|---|---|
| 与现在事实相反 | If + 主语 + 动词过去式（be用were） | 主语 + would/could/might + 动词原形 | 1. If I were you, I would study harder. 2. If it rained, we might stay home. | – 假设与当前情况相反 – be动词永远用were（即使主语是单数） – 口语中可省略if，用倒装：Were I you… |
| 与过去事实相反 | If + 主语 + had + 过去分词 | 主语 + would/could/might + have + 过去分词 | 1. If I had studied harder, I would have passed the exam. 2. If she had called me, I could have helped her. | – 假设过去未发生的事 – 固定搭配：If it hadn’t been for…（要不是因为…） – 混合时间句：过去条件+现在结果（如：If I had known, I would come now.） |
| 与将来事实相反 | 形式1：If + 主语 + were to + 动词原形 形式2：If + 主语 + 动词过去式（更口语化） | 主语 + would/could/might + 动词原形 | 1. If I were to win the lottery, I would buy a house. 2. If it snowed tomorrow, we might cancel the trip. | – 假设未来极不可能发生的事 – were to更正式，多用于书面语 – 可与unless替换（如：Unless it snowed, we would go.） |
