虚拟语气用于条件状语从句的情况

南昌十九中  宋焘

虚拟语气表示说话人的愿望、假设、猜测或建议，而不表示客观存在的事实。虚拟语气通过谓语动词的特殊形式来表示，下面介绍虚拟语气用于条件状语从句的一些情况。
1.表示与现在事实相反的假设时，条件状语从句中的谓语动词用“过去式（be的过去式用were）”，而主句中的谓语动词用“would（should, could, might）+动词原形。”例如：
If I were you, I should study English.
If he had time, he would attend the meeting.
2.表示与过去的事实相反的假设时，条件状语从句的谓语动词用“had +过去分词”，主句中的谓语动词用“would（should, could, might）+have +过去分词”。例如：
If you had taken my advice, you wouldn’t have failed in the examination.
3.表示与将来事实相反的假设时，条件从句和主句所用的谓语动词怀“表示与现在事实相反的假设”的谓语动词相同，或者条件从句中用“were to（should）+动词原形”。例如：
If you come tomorrow, we would have the meeting.
If it were to rain tomorrow, the meeting would be put off.
注意:

1.当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间来调整。例如：
  If you had worked hard, you would be very tired.(从句说的是过去,主句指的是现在.)
2.有些情况下可以省略if,用“were, have, should +主语”结构. 例如:
Were I in school again(If I were in school again), I would work harder.
Had you been here earlier(If you had been here earlier), you would have seen him.
Should there be a meeting tomorrow(If there should be a meeting tomorrow), I would come.