虚拟语气的含蓄条件句的运用请问，虚拟语气的含蓄条件句怎么样运用？其他语法书和网页上说明含蓄条件句都只是“用一些例句来列举说明含蓄条件句有多少种情况”而已，但没有教会

Question

虚拟语气的含蓄条件句的运用
请问，虚拟语气的含蓄条件句怎么样运用？
其他语法书和网页上说明含蓄条件句都只是“用一些例句来列举说明含蓄条件句有多少种情况”而已，但没有教会怎么运用含蓄条件句：是用介词短语、不定式等代替if条件句的哪一部分而构成含蓄条件句的。我希望高手们能列举含蓄条件句的一些构成规则，谢谢！
请问，怎么判断是对哪个时间的虚拟，然后怎么仿照if引导的句式结构呢？请高手具体说明。

Answer 1

你提出来的是同一论题的不同的方面，下面分两方面作答：
一、含蓄条件句：
所谓含蓄条件句就是利用语境不直接说出条件的句子。这种句子可以分为两类：一种是广义的含蓄条件句，另一种是狭义的含蓄条件句。
1. 广义含蓄指的是不用连词 if 或 unless 介绍条件，而是改用其他方式。事实上这些表达方式也是同样是条件状语。
（1）用介词引入条件：
* but for（如不是, 如没有）：注意，凡是出现这个复合介词的句子，必须要用虚拟语气，如：
We would have had a pleasant journey but for the rain.（= We would have had a pleasant journey if it hadn’t rained.）
* without/with (在不具备/具备…的条件下), 如：
Without his help, I could not have done it well. (=If he hadn’t helped me, I could not have done it well.)
With favorable winds, we might have got there in tow days. (= If there should be favorable winds, we might have got there in tow days.)
* under （在…条件下）
We could have done better under more favorable conditions. （= We could have done better if we were to be under more favorable conditions.）
（2）分词短语充当条件（分词短语本身就具有充当条件状语的功能），如：
Given a certain oppertunity, he could have shown more talent. (= If he hade been given a certain oppertunity, he could have shown more talent.)
（3）表示不具备条件的连词连词：but,but that,or或otherwise不定式短语
They would have resisted but that they lacked courage. （= They would have resisted if they hadn’t lacked courage. 要不是缺乏勇气她们会抵抗的. ）
诸如此类，不一而足。
2. 狭义含蓄指的是不用任何语言方式显示条件，而是把条件隐藏在具体的原环境中，
（1）用上下文暗示条件，如：
I was so busy then, otherwise, I would have finished it. （If I hadn’t been busy then, I would have finished it.）
It rained yesterday, or I would have gone camping. (If It hadn’t rained yesterday, I would have gone camping.)
（2）用委婉语气暗示条件，如：
Would you mind opening the window? (=Would mind if I opend the window.)
Could you do me a favour to pass me the book? (= You would do me a favour if you should pass me the book. )
（3）用表示愿望的语气暗示条件，如：
Long live the Chairman Mao! (= If Chairman Mao should live long.)
（4）用其他语言环境暗示条件，如：
That would be fine. ( =省略了If you should do it.)
You might saty here forever. (=省略了 If you wanted to.)
I would not have done it. (=省略了 If I were you.)
二、含蓄条件句的虚拟时间
含蓄条件句是一种不出现条件从句的句子，也就是说它只是单独的一个主句形式，因此谓语动词就是主句所要求的形式.
1. 表示对过去的虚拟：情态动词 would/could/should/ought to + have done
2. 表示对现在或将来的虚拟：情态动词 would/could/should/ought to + do