82.The cave might never have been dis covered had not the entrance been spotted by the distinguished French po tholer,Berger.Since its discovery ,it has become a sort of potholers’ Everest.(新概念3，L42)
要不是法国著名的洞穴探险家波格发现了这个洞的入口，这个洞穴也许永远不会被发现。自从这个洞被发现以来，她就成了洞穴探险者的“珠穆朗玛峰”。
经典句型解析之82：if虚拟语气用法及其省略后的倒装用法解析
这是表示与过去事实不相符的虚拟语气结构，句中的非真实条件句had not the entrance been spotted by...由于省略了if,因此要用倒装句式。这个句型特殊就在于它采用了虚拟语气，而且if省略，并且，从句比较罕见地放在主句的后面,其not也与助动词一起提至主语之前。
关于if虚拟语气用法，许多同学谈虎色变，自动放弃；其实搞懂了也很好，可以在作文里信手拈来，作文高分也是拿到手软。作为英语中最难掌握的虚拟语气，首先需要掌握其标准形式，再掌握省略if的虚拟句型。
一、含if句的几种标准形式：
1、对现在情况的虚拟
条件从句中谓语动词用一般过去式，主句用“would/should/might/could 动词原形”形式，表示对现在不可能实现情况的'假想。
主句：主语＋would/should/might/could＋动词原形
从句：动词过去式did(虚拟语气中be→were，也可用was)
Eg：If he studied at this school, he would know the enviornment around the school very much.
如果他在这所学校学习的话，他会很了解周边环境。
If I saw him now，I would be very happy.
如果现在你看见他，我将很开心。
If he improved his IT skills, he’d (= he would) easily get a job.
他如果提高了自己的IT技能，就会容易找到工作。
I should stay in bed if I were you.
我要是你，就卧床休息。
If I didn’t apologize, I’d feel guilty.
如果我不道歉，我会感到内疚。
If Dad were here, he would know what to do.
如果爸爸在这儿，他会知道怎么做的。
If we were to offer you more money, would you stay? = Were we to …
假如我们给你加钱，你愿意留下吗？
The news would be interesting if (it were) true, but it’s not true.
如果这消息是真的，那会很有趣，但它不是真的。
2、对过去情况的虚拟
条件从句中谓语动词用过去完成式，主语用“would/could/should/might have 动词的过去分词”形式。
也就是假设性地提出过去的未发生的条件
主句：主语＋would/should/might/could have＋动词过去分词
从句：had＋动词过去分词
Eg：If I had read the book, I would have told you about it.
如果你读过那本书，我就会给你讲一讲那本书。
If it had not rained yesterday, we would have played football.
如果昨天不下雨，我们将踢足球。
If you had not been in such a hurry, you would not have put sugar into the sauce instead of salt.
如果你不那么着急，就不会错把糖当作盐放进蘸料里面了。
They would never met if she hadn’t gone to Emma’s party.
她如果不去参加艾爱玛的聚会，他们就永远不会相会。
I would have phoned you, but there wasn’t time.
我本想给你打电话，但没有时间。
I could have warned you if I had known where you were.
我要是知道你在那里的话就提醒你了。
If you had worked harder, you would have passed your exams.
要是你努力一点，就通过考试了。
If I hadn’t seen it with my own eyes I wouldn’t have believed it.
要不是亲眼看见了，我不会相信的。
If I’d had time, I would have gone to Graham.
如果我那时有时间的话，我本来会去看望…的。
If I had seen the advertisement in time I would have applied for the job.
我要是及时看到了这则广告，我就应聘那份工作了。
If you had studied, you would have passed the test.
如果你完成学习了，你就会通过考试。
The harvest would have been good if it had rained.
如果下了雨的话，收成会好的。
Had I known that (= If I had known that) I would never have come.
要是早知道，我绝不会来的。
Had we known about it earlier, we could have warned people of the danger.
假如早点知道这件事的话，我们就能提醒人们有危险了。
3、对将来情况的虚拟
在表示与将来事实相反的条件从句中，谓语动词可用should do,were to do或动词的过去式三种形式表示，但意义略有不同。should表示的可能性最大，动词过去式的可能性次之，were to do 的可能性最小。
主句：主语＋would/should/might/could＋动词原形
从句：should＋动词原形/did/were to＋动词原形。
Eg：If he should go to Harvard University, he would make full use of his time.
如果他要上哈佛大学的话，他就会充分利用他的时间了。
If it were to snow/should snow tomorrow，we would cancel the 1000-meter race.
如果明天下雪，我们将取消1000米赛跑。
I would be amazed if I got the job.
我要是得到这份工作就会喜出望外。
What would you do if you won a million pounds?
如果你赢了100万英镑，你会做什么？
What would you do if you lost your job?
要是失去了工作你会怎么办？
If I were to refuse they’d be very annoyed.
如果我拒绝，他们会很气恼的。
=[正式] Were I to refuse they’d be very annoyed.
倘若我拒绝，他们会很气恼的。
4. 混合的虚拟语气
从句发生的动作和主句发生的动作，不在同一个时间范围内发生。
If he were alive now, he might have finished his scientific researches on the bridge building three years ago.
如果他现在还活着，他可能三年前就完成了他的桥梁建筑科研工作了。
If it had not snowed yesterday, we would be on the way to Shanghai.
要是昨天不下雪的话，我们现在就应该在去上海的路上了。
二、省略if的虚拟语气用法
在含if的虚拟语气句子中，if是可以省略的，此时采用倒装形式，有情态动词、助动词、be的，把这些词语提之于句首且放在主语之前即倒装，如果从句仅仅是实意动词一般过去时的if的虚拟语气句子，应加上did完成省略if和倒装语序。如：
1.Should you buy a home from Lovell, the company promises to buy it back at the same price after three years.
如果你从洛弗尔公司买房子，该公司承诺3年后以同样的价格再购回。《柯林斯高阶英汉双解学习词典》
正常虚拟句：
If you should buy a home from Lovell, the company promises to buy it back at the same price after three years.
2.Should you change your mind,no one would blame you.
要是你改变主意的话，谁也不会责怪你。
正常虚拟句：
If you should change your mind,no one would blame you.
3.Had I known that I would never have come.
要是早知道，我绝不会来的。《牛津高阶英汉双解词典》
正常虚拟句：
If I had known that I would never have come.
4.Had he succeeded, he would have acquired a monopoly.
要是他当时成功了，他就会取得垄断地位。
正常虚拟句：
If he had succeeded, he would have acquired a monopoly.
5.Were it not for your help,I would still homeless.
要是没有你的帮助的话，我仍然会是无家可归。
正常虚拟句：
If it were not for your help, I would still homeless.
6.Had it not been for the unusually bad weather,the rescue party would would have been able to
save the stranded climber.
要不是有反常的坏天气，抢救小组是能救出那个陷入困境的登山者的。
正常虚拟句：
If it had not been for the unusually bad weather, the rescue party would would have been able to
save the stranded climber.
注意not在句子中的位置。且不适宜采用否定连写缩略形式。
我们可以说：Were it not the expense, I would go abroad now.
也可以说：Were not it the expense, I would go abroad now.
（今天专题所给的经典例句就是这样）
但不能说：Weren't it for the expense, I would go abroad now.
特别注意
1.如果从句仅仅是实意动词一般过去时的if的虚拟语气句子，应加上did完成省略if和倒装语序。如：
Did we know her circumstances, we could do something to help her.
假如现在我们知道她的处境，我们本来可以采取措施帮助她的。
正常虚拟句：
If we knew her circumstances, we could do something to help her.
Did he have money,he would buy that villa.
要是他有了钱，他会买下那栋别墅。
正常虚拟句：
If he had money, he would buy that villa.
注意谓语动词是实意动词have的各种形式时，不能把句子转换为：
Had he money, he would buy that villa.(错误)
2.这种省略if的虚拟句子可以放在主句之前，也可以放在主句之后。例如：
The cave might never have been dis covered had not the entrance been spotted by the distinguished French po tholer,Berger.(新概念3，L42)
如果不是法国著名的洞穴探险家波格发现了这个入口的话，这个洞穴可能永远不会被发现。
The millons of calculations involved,had they been done by hand,would have lost all practical value by the time they were finished.
所涉及的数以百万计的计算，如果是手工完成的话，到完成时就会失去所有的实际价值。
这个省略if的虚拟句子的位置则更加自由。
