5. 以上句型可以转换成以下形式：
　　1)条件状语从句省略if：在书面语中，如果条件状语从句的谓语中有were, had 或should, 就可以省略if, 并将were, had 或should 放到句首，谓语主语之前，用 “Were/Had/Should + 主语”的形式。这种虚拟语气在意义上与带if 的条件状语从句相同。当然，如果从句没有were, had, 或should,就不能省略if.
　　Now let’s look at some examples:
　　If I were to do it, I’d do it some other way. →Were I to do it, I’d do it some other way.
　　If you should fail, try again. →Should you fail, try again.
　　If you had been here earlier, you would have seen him. →Had you been here earlier, you would have seen him.
　　但是，If you came tomorrow, we would have the meeting.这句话if 就不能省略。
　　而且，在虚拟条件状语从句中，省略了if的倒装形式的句首不能用动词的缩略形式。如我们可以说：
　　Were it not for the expense, I would go to Italy.
　　但不能说：Weren’t it for the expense, I would go to Italy.
　　Please do not use “if”：
　　如果我是你，我每天早上就早起床。
　　Were I you, I would get up early every morning.
　　假如你昨天早十分钟到达火车站，你就赶上火车了。
　　Had you arrived at the station ten minutes earlier yesterday, you could have caught the train.
　　要是明天有会议，我就会来。
　　Should there be a meeting, I would come.
　　2)用介词短语代替条件状语从句。(可以改为条件状语从句)。例如：
　　Without air, there would be no living things.
　　But for your help, I couldn’t have done it.
　　Without electricity human life would be quite different today.
　　Now let’s do some translation. 请用介词短语代替条件状语从句。
　　要不是你的帮助，我就失败了。
　　But for (except, without) your help, I would have failed.
　　如果没有恰当的控制手段，核反应堆就会爆炸。
　　Without proper means of control, a nuclear reactor would explode.
　　3)用其他方式代替条件状语从句(可以改写为条件状语从句。)例如：
　　It would produce bad results to do that. 用动词不定式 =If you did that/should do that, it would produce bad results.
　　She would have come, but she wasn’t informed, nor invited. (用but.)=She would have come, if she had been informed or invited.
　　A more responsible person would not have left the work half done. 一个更负责的人是不会把工作做到一半就不管的。(用比较级) =If you (he, she) were more responsible, you (he, she) would not have left the work half done.
　　Now let’s do some translation:
　　聪明一点的人是不会干出这等蠢事的。
　　A wiser man would not have done such a foolish thing.
　　我应该早点写完这封信，但我一直很忙。