语言是灵活多变的，表达是丰富多彩的。有的时候虚拟语气的表现形式也显得非常灵活，比如就说其中的虚拟条件吧——它有时会以if从句来表示，但有时会用某种短语来表示，比如不定式短语、分词短语、介词短语等等。

1. if 的隐含

I should be happy to go with you. 如果能与你一起去，我将很高兴。

句中的不定式短语to go with you就是表示虚拟条件的，它相当于if I could go with you。这句话的言外之意是：可惜我不一定有机会同你一起去。

To have studied harder, you would have passed the examination. 你学习更用功些，你早就考及格了。

句中的不定式短语to have studied harder也是表示虚拟条件的，它相当于if you had studied harder。句子的言外之意是：可惜你当时没有更用功我，所以你就没有考及格。

Failing this time, what would you do？假若这次失败，那你怎么办？

句中的分词短语failing this time表示虚拟条件，相当于if you failed this time。其言外之意是：尽管失败的可能性很小，但还是有可能会失败，假若失败了，那怎么办？

Without your help, we couldn’t have succeeded. 如果没有你的帮助，我们就不会取得成功。

句中的介词短语without your help表示虚拟条件，相当于if you hadn’t given us help。其言外之意是：好在你帮助了我们，所以我们取得了成功。

I didn’t know that he was a cheat, or else I wouldn’t have believed him. 我不知道他是个骗子，不然我也不会相信他了。

句中的or else隐含着一个虚拟条件，它相当于if I had known he was a cheat。句子的言外之意是：当是我竟然相信了他。

2. if 的省略

在虚拟条件句中，有时可将引民虚拟条件句的连词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。如：

如果她在这里，她也同意的。

If he were here, she would agree too.

→Were she here, she would agree too.

假若明天下雨，我们只好推迟这场比赛。

If it should rain tomorrow, we should have to put off the match.

→Should it rain tomorrow, we should have to put off the match.

要是我们当时早点找到他的话，我们就可以救活他。

If we had found him earlier we could have saved his life.

→Had we found him earlier we could have saved his life.

注意，如果条件从句的谓语为否定式，其中的否定词not应置于主语之后，而不能与were, should, had 等缩略成Weren’t, Shouldn’t, Hadn’t而置于句首。

我如不是警告了你，你就可能丧命了。

正：If I hadn’t warned you, you could have been killed.

正：Had I not warned you, you could have been killed.

误：Hadn’t I warned you, you could have been killed.

另外，有时省略if后提前到句首的had可能不是助动词，而是实义动词。如：

Had I time, I would go with you. 假如我有时间，我就同你们一起去。

句中的had不是构成过去完成时的助动词，而是表示“有”，如果不省略if，其完整形式为：If I had time, I would go with you.

引用地址: http://www.yygrammar.com/Article/201109/2551.html