三、虚拟条件句中的虚拟语气

　　1.表示与现在事实相反的情况

　　从句：If+主语+did(be动词用were)

　　主句：主语+ should/would/might/could+do

　　If there were no air or water,there would be no living things on the earth.

　　如果没有水和空气，地球上就不会有生物。(事实：地球上既有空气也有水)

　　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 knew his telephone number,I would tell you.

　　如果我知道他的电话号码，我就会告诉你。(事实：不知道)

　　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 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)

　　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)

　　3.表示与将来事实相反的情况

　　从句：①if+主语+were to do

　　②if+主语+should+do

　　③if+主语+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：不可能来)

　　If she were to be here next Monday,I would tell her about the matter.

　　如果她下周一来这儿的话，我就会告诉她这件事的始末。(事实：不可能来)

　　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：不可能下雪)

　　注意事项：

　　2

　　① 错综时间句：即虚拟条件状语从句与虚拟主句中谓语动作的时间不一致。

　　If he knew her,he would have greeted her that day.

　　如果他认识她的话，他肯定会去问候她了。

　　If they had informed us,we would not come here now.

　　如果他们通知过我们的话，我们现在就不会来这里了。

　　If I had worked hard at school,I would be an engineer,too.

　　如果我在学校学习刻苦的话，我现在也会成为一个工程师了。