请问一下英语中虚拟语气怎么用，谢谢了！

虚拟语气分为：与现在事实相反，与过去事实相反，与将来事实相反
第一种：与现在事实相反,从句用过去时，did或were,主句用would+动词原形
例句:If I were you,I would not study English.
第二种：与过去事实相反，从句用had done，主句是would/could/should have done
例句：If you had come yesterday,you would/should/could have seen her
第三种：与将来事实相反，从句分三种
1、与现在事实相反用法一样
2、were to do
3、should do这里should不可替换，主句用could/would +动词原形
例句
1.If you came tomorrow,you would see me
2.If you were to come tomorrow,you could/would see me
3.If you should come tomorrow ,you could/would see me
这些用法必须是背下来的，没有什么捷径可走，有的时候，阅读里的句子是混杂的，可能主句与过去相反，从句与现在相反，只要熟背我上面所说的，就能分别取从句和主句，加油吧

虚拟语气是在和现在事相反的状态下；或者是假设{ if i were you }，或建议的状态下用

有三种形式1 与过去事实相反 从句用had done 主句用should could might would have done
2与将来相反 从句用were did 或were to 或should do 主句用同上但是加原型
3于现在相反 从句用were 或did 主句用同上但是加原形