1、虚拟语气的具体含义：
虚拟语气，顾名思义就是一种假想，通常是人们表达与事实情况相反或难以实现的情况的一种语气。但是当说话者要表示主观愿望或某种强烈情感，欲强调其所说的话是基于自己的主观想法，愿望，假想，猜测，怀疑或建议，而不是根据客观实际时，也可用虚拟语气。
2、与现在事实相反的情况：
从句：If+主语+动词一般过去时 (Be动词则用were)；主句：主语+ should/would/might/could+do；例句：If I were you，I would take an umbrella.
3、与过去事实相反的情况：
从句：If+主语+had+done；主句：主语+should/would/might/could+have done；例句：If he had taken my advice，he would not have made such a mistake.
4、与将来事实相反
从句：if+主语+were to do、if+主语+should+do、if+主语+动词一般过去式（be动词用were）；主句：主语+should/would/might/could+do。
