虚拟语气-if引导的非真实条件句

虚拟语气-if引导的非真实条件句
1. 真是条件句和非真实条件句
一般而言，虚拟语气用于条件状语从句中是考生们最常见、最常考到的虚拟语气语法点。

此种虚拟语气形式也就本课件特定讲解的“if引导的非真实条件句之虚拟语气”。

再讨论此类虚拟语气之前，有必要说明一点：并非所有包含“if引导的非真实条件”从句的句子都是虚拟语气句子。

在英语中，虚拟语气表示动作或状态与事实相反，或不可能发生的情况。

因此要判断类似句子是不是虚拟语气，通常的标准是：假设条件不符合客观事实或者实现的可能性极其微小的，通常就是虚拟语气；反之则不是。

请理解区别以下句子：
(1)If you don’t hurry up, you will miss the bus. 如果他不快点，他将错过巴士。

( 真
实)
(2)If I were you, I would go at once. 如果我是你，我马上就会去。

（非真实，
虚拟语气）
2. 虚拟语气用于条件状语从句中
1) if假设的条件与现在事实相反或不可能发生。

则条件状语从句用一般过去时（任何be动词的原来形式一律改用were），主句用“would(should, could, might)+动词原形”。

请理解以下句子：
(1) If I were you, I would work hard.
(2) If we had time, we could play the game again.
2) if假设的条件与过去事实相反或不可能发生。

则条件状语从句用“had+过去分词主句”，主句用“would(should, could, might)+have+过去分词”。

请理解以下句子：
(1) If he had taken my advice, he would have passed the exam.
(2) If I had known your telephone number, I would have called you.
3) if假设的条件与将来的事实可能相反或不可能发生：条件状语从句：①
一般过去时,②“should +动词原形”,③“were to+动词原形”；主句：“would(should, could, might)+动词原形”。

其中①的情况包括一些在条件状语从句中用一般时表示将来时的特殊动词和动词词组，如“go，arrive，come，leave，start，stay，return, play, do, have, work, wear, spend, see, meet，there be”等，请随带记忆。

请理解以下句子：
（1）If there were rain tomorrow, the game would be put off.
（2）If it were to snow tomorrow, they would not go out.
（3）If it should rain tomorrow, I would stay at home.
P.S省略if的虚拟语气
如果从句中含有were/ should/ had时，则可以把这三个词置于句首，省略if，并在从句中采用倒装语序。

请理解一下句子。

（1）If she were here, she would agree with us.→Were she here, she would agree with us.
（2）If it should happen, what would you do? →Should it happen, what would you do?
（3）If he had recognized me, he would have come over. →Had he recognized me, he would have come over.
3. 总结
以上3大类情况属于if引导的非真实条件句的虚拟语气的常见基本形式，但其所有形式绝不仅限于此。

如：
If you had followed my advice, you would be better now. 这显然是假设条件与过去相反，而主句表达现在情况的混合虚拟语气句，并且没有任何语法错误。

因此需要说明的是，要学好虚拟语气，对句意的理解才是根本。