虚拟语气定义：如果句子表示的是与事实相反的主观设想或者尚未发生但发生几率很小的事态，那么句子的谓语动词使用虚拟语态。

　　虚拟语气句子结构

　　1.表示与现在事实相反的情况

　　从句：If+主语+动词一般过去时(Be动词用were)

　　主句：主语+ should/would/might/could+do：

　　If I were you，I would take an umbrella.

　　如果我是你，我会带把伞。（事实：我不可能是你）

　　If I had any money with me，I could lend you some.

　　如果我带钱了，我就会借给你些。（事实：没有带钱）

　　2.表示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

　　If I had got there earlier，I should/would have met her.

　　如果我早到那儿，我就会见到她。（事实：去晚了）

　　If he had taken my advice，he would not have made such a

　　mistake.

　　如果他听我的劝告的话，就不会犯这样的错误了。（事实：没有听我的话）

　　3.表示与将来事实相反

　　从句：①if+主语+were to do

　　②if+主语+should+do

　　③if+主语+动词一般过去式（be动词用were）

　　主句：主语+should/would/might/could+do

　　If he should come here tomorrow，I would talk to him.

　　如果他明天来这儿的话，我就跟他谈谈。（事实：来的可能性很小，不可能）

　　If there were a heavy snow next Sunday，we would go skating.

　　如果下周日下大雪，我们就去滑冰。（事实：下雪可能性很小，不可能）