if引导的虚拟条件句.ppt

虚拟语气-------- if 引导的虚拟条件句
虚拟语气(if 条件句)
含义:其假设是不可能或不大可能发生或实现的;主从句皆须用虚拟
If the working conditions are not too bad, I will accept the job. (真实条件句:对现有事实的一种陈述,使用的是陈述语气)---表达一种看法(工作条件状况未知)
If the working conditions were not too bad, I would accept the job. (非真实条件句---虚拟语气)表达一种假设(与事实相反---工作条件已经很糟糕了)
If 引导的虚拟条件句的三种类型
带if的虚拟条件句
省略if的虚拟条件句
隐藏if的虚拟条件句
与现在事实相反:if条件句用一般过去时(动词be用were),主句用would(should/could/might)+动词原形
Ⅰ、带if的虚拟条件句
eg:
I am sorry I am very busy just now. If I had time, I would certainly go to the movies with you.
If you could bear the loneliness, you might eed.
与将来事实相反(推测将来):if 条件句中用过去时,或should/were to+动词原形,主句用would (should/could/might)+动词原形。
eg.
If she were here this evening, we would go shopping.(从句:一般过去时)
If Mary were to marry Jack, she would be happy.(从句:were+动词不定式)
If she should know it, she would tell me. (But I doubt)(从句:should+动词原形)
If we hadn’t made adequate preparations, the party wouldn’t have been so essful.
The flood might have caused great damage to the people, if we hadn’t built so many dams .
与过去事实相反:if 条件句中用过去完成时,主句用would(should/could/might)+have+过去分词。
条件从句
结果主句
与现在事实相反
If + 主语+ 过去式
主语+ would / should / could / might do
与将来事实相反
If+主语+过去式
主语+ would / should / could / might do
were to do /should/could do )
与过去事实相反
If + 主语+ had+过去分词
主语+ would / should / could / might have done
If引导虚拟条件句中的谓语动词变化
与将来事实相反时从句中的三种谓语v变形:
一般过去时
were + to do
Should/could do
注:这三种均可用,不同的是在表示推测将来的时候,可能性的程度不同。
If it snowed tomorrow, I should / would stay at tomorrow.(常用形式)
If it were to snow tomorrow, …....(可能性较小)
If it should snow tomorrow, ……(可能性较大)
Ⅱ.虚拟条件句中if的省略或隐藏
的虚拟条件句
隐藏 if 的虚拟条件句-无“条件”的虚拟语气句子
1. 省略if 的虚拟条件句(主要用于书面语)
在虚拟条件句中,有时可将引导虚拟条件句的连词if省略,但此时应用倒装句型,即将从句中的were, should, , had 等提到句首。