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虚拟语气分三种情况来掌握：
1、虚拟条件句。
2、名词性虚拟语气。
3、虚拟语气的其他用语。
一、虚拟条件句：
条件状语从句是非真实情况，在这种情况下要用虚拟语气。
1、条件从句与现在事实不一致，其句型为：
If 主语+过去时，主语+should(could, would, 或might)+动词原形，如：
If I were you, I would study hard.
If it rained, I would not be here now.
2、条件从句与过去事实不一致，句型为：
If 主语+had+过去分词，主语+should(could, would, 或might)+have+过去分词，如：
If the doctor had come last night, the boy would have saved.
If I had not studied hard, I would have failed in the exam last term.
3、条件从句与将来事实不一致，句型为：
+do，主语+should(could…)+ 原形 do
过去时(与现在事实条件句一样)。
If it should rain tomorrow, we would stay at home.
If I were to go to the moon one day, I could see it with my own eyes.
If you missed the film to night, you would feel sorry.
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