第21章 条件句型
句型258：if引出的条件状语从句
例句：If we can change our thoughts, we can change the world.
【★】：假如我们能够改变我们自己的思维，我们就能够改变世界。
【句型点拨】：由if引导的真实条件句，从句的假设情况是可能发生，就是真实条件句，这种条件句中的谓语动词都用陈述语气。如果从句是偶然假设的情况或是发生的可能性不大的情况，条件句谓语用虚拟语气，其句型公式为“动词过去式（从句），would / could / might＋动词原形（主句）”。该句式表示现在及将来情况的虚拟假设。如果与过去事实相反，条件分句中的谓语动词要用过去完成式，主句中的谓语动词要用would (should, could, might) ＋现在完成式结构，表示假设的条件在过去没有实现。
If I can turn out more work like that perhaps I really will be able to make a career of it.
★如果我能够做出更多这样的成绩，也许我真有可能以此为职业。
If the decimal point is moved, a number will become either smaller or bigger.
★如果移动小数点，一个数就会变小或变大。
If we want everyone to be healthy, wealthy and happy, strict birth control is quite essential.
★如果我们想使每个人都能过健康、富裕和幸福的生活，就必须实行严格的计划生育。
If you command wisely, you'll be obeyed cheerfully.
★指挥有方，人人乐从。［谚语］
If you don't try hard to build up a large vocabulary, you can't expect to gain a good command of the English language.
★如果你不尽力提高词汇量，你就不要期望掌握好英语。
If you have the will to win, you have achieved half your success.
★如果拥有取胜的意志，你已经实现了成功的一半。
If you show that you have initiative, you will sooner or later be promoted.
★如果你展示出你独挡一面的能力，你迟早会得到提升的。
If you want to make your way, you must learn to work hard while you are still young.
★你要想成功，就得学会趁着年轻多多努力。
If he had steady wages, he would be able to feed himself and help his family.
★如果他有稳定的收入，他一定能够养活自己并帮助养家。
If we had the help of a bank, we would be able to expand our business.
★如果我们有银行的帮助，我们就一定能够扩大我们的业务。
The teacher told me that it'd be a miracle if I passed the examination.
★老师告诉我，如果我能够通过这次考试那将是一个奇迹。
What would happen if all government money for research were cut off?
★如果政府对这项研究的投资都被取消了，会发生什么事情？
If the whole operation had not been planned beforehand, a great deal of time and money would have been lost.
★如果不是在事先对整个手术做了周密的计划，将损失大量的时间和一大笔钱。
Rebecca would have told me earlier if she did not like her house she bought last month.
★如果她不喜欢她上个月买的房子，丽贝卡早就会告诉我了。
If he had been a little less rigid about things, his daughter would not have left home at such a young age.
★如果他从前对事情不那么严格苛刻的话，他女儿就不会这么年轻就离家出走了。
If you had spent half as much time as your studies as your elder sister did, you could have made the honor roll.
★如果你在学习上花上你姐姐一半的时间，你一定会上优秀生名册的。
句型259：unless引出的条件状语从句
例句：He won't finish his work in time unless he works hard.
【★】：除非他努力干，否则就不会按时把他的活干完。
【句型点拨】：unless在意思上相当于if...not，有时在引导真实条件句时可与if...not互换。如果主句是一般现在时，从句多用一般现在时代替一般将来时。
You will never succeed unless you try.
★你若不尝试，就绝不会成功。
No one becomes rich unless he enriches another.
★如果没有让他人变得富有，一个人就不会富有。
Unless you give yourself to some great cause, you haven't even begun to live.
★除非投身于某项伟大事业，否则你就还未开始真正的生活。
Many chemical changes will not take place unless materials are heated to a high temperature.
★假如不把材料加热到高温，许多化学变化就不会发生。
No flow of electric current occurs unless there is a difference of potential.
★除非有电位差，否则就不会产生电流。
Unless the air is first removed from a bulb, the filament will burn up.
★ 假如不先把灯泡里的空气抽净，灯丝就会烧断。
句型260：as long as引出的条件状语从句
例句：I'll let you use the room as long as you keep it clean.
【★】：只要你保持房间清洁，我就让你使用这个房间。
【句型点拨】：作为复合从属连词，as long as可以写作so long as，它引导的条件状语从句表示的是一段时间里的事情，因而从句的谓语动词一般是表示状态的或表示延续动作的动词。as/so long as所在的从句中，需用一般现在时代替一般将来时。
You can go out, as long as you promise to be back before 11 o'clock.
★只要你答应11点钟前回来，你可以出去。
You may use the room as long as you clean it afterward.
★你可以随意用这个房间，只要你用完后弄干净就行。
It doesn't matter what you do as long as you enjoy it.
★只要自己喜欢，你做什么并不重要。
As long as the world lasts, there will be mistakes.
★只要世界延续，就会有错误。
This saves an enormous amount of electricity, as long as the electromagnet is kept at these low temperatures.
★只要使电磁铁保持这样的高温，用这种方法就能节约大量电能。
A man is not old as long as he is seeking something. A man is not old until regrets take the place of dreams.
★一个人只要还有所追求，他就没有老。直到后悔取代了梦想，一个人才算老。
句型261：in case引出的条件状语从句
例句：In case the house burns down, we'll get the insurance money.
【★】：如果房子烧毁，我们会得到保险金。
【句型点拨】：作为复合从属连词，in case的意思是“若”、“如果”、“万一”。它往往带有“为……的可能性而作准备”。
In case it rains, do not expect me.
★如果下雨，就不要等我了。
In case you fail, don't be discouraged. Keep trying.
★假如你失败，不要气馁。要继续努力。
In case John comes, please tell him to wait.
★假如约翰来了，请让他等一下。
In case you cannot come tomorrow, please notify us beforehand.
★万一你明天来不了，请事先通知我们。
In case you need something, please don't hesitate to ask me.
★如果你需要什么东西，请不要客气地对我说。
句型262：if only引出的条件状语从句
例句：：If only you hadn't told Jackie what I said, everything would have been all right.
【★】：要是你没有把我的话告诉杰吉就好了，那样就不会出什么问题了。
【句型点拨】：if only是if的强调式，可以用来表达强烈的愿望或遗憾，意思是“但愿……，要是……就好了”，这时谓语动词多用虚拟语气。表示条件时，可以把if only写成only if。
We'll be all right if only we can get to the next petrol-station.
★要是我们能够到达下一个加油站就好了，那我们就没有问题了。
I'll help you if only you tell me the truth.
★只要你对我讲实话，我就帮助你。
You win only if you aren't afraid to lose.
★只要不怕输你就会胜出。
Electrons will flow along a wire only if there is a difference of electric pressure along the conductor.
★只有当导体存在电压差的时候，电子才会沿导体流动。
Only if we persist in carrying out the open-door policy, we will achieve greater success in every field.
★只要我们坚持改革开放，我们就能在各个方面取得更大的成就。
If only I had known it, I wouldn't have troubled him.
★要是早知道那件事，我就不会麻烦他了。
句型263：on condition that引出的条件状语从句
例句：You may borrow the book, on condition that you don't lend it to anyone else.
【★】：你可以借这本书，条件是别把它借给别人。
【句型点拨】：on condition that引导的从句一般位于主句之后，它表示说话人提出的某一条件。
The design is likely to be approved on condition that the cost is reasonable.
★若造价合理，这个设计很可能被批准。
We can reach an agreement on condition that you are reasonable.
★如果你理智一点，我们可以达成一致意见。
You can go swimming on condition that you don't go too far from the river bank.
★只要你不远离岸边，你可以去游泳。
On condition (that) you cut off the relation with him, you won't be harassed.
★只要你断绝和他的一切关系，他就不会再来骚扰你了。
句型264：suppose（that），supposing（that）引出的条件状语从句
例句：Supposing (that) you are wrong, what will you do?
【★】：假定你是错的，你怎么办？
【句型点拨】：边际从属连词supposing（that）或suppose（that）的意思是“倘若，假使”、“假如……的话”，它引导的从句一般位于句首。
Supposing we can't get the necessary equipment, what should we do？
★要是我们没有弄到必要的设备，怎么办呢？
Suppose you had a million pounds, how would you spend it？
★设想你有一百万英镑，你会怎么花呢？
Suppose they did not believe him what would they do to him？
★如果他们不相信他，他们会对他怎样？
Supposing they can't come, who will do the work？
★如果他们不来，这事谁来干？
Suppose / Supposing that I don't have a day off, what shall we do？
★假如我没有假，那该怎么办？
Suppose he doesn't come, what shall we do？
★他要是不来，我们该怎么办？
句型265：provided（that），providing（that）引出的条件状语从句
例句：She may come with us provided (that) she arrives in time.
【★】：如果她及时赶到，她可以和我们一道去。
【句型点拨】：边际从属连词provided（that），providing（that）的意思是“以……为条件”，它们所在的从句用一般现在时代替一般将来时。
Providing (that) there is no opposition, we shall hold the meeting here.
★如果没有人反对，我们就在这儿开会。
She will go provided her friends can go also.
★如果她的朋友去，她就去。
We can do whatever we wish to do provided (that) our wish is strong.
★如果我们的愿望很强，我们就能做任何自己希望做的事情。
It is a simple task provided (that) one is willing to pay the price in time and concentration.
★假如愿意在时间和精力上付出代价，这就是一项简单的工作。
The volume of gas is proportional to its absolute temperature providing that its pressure remains constant.
★若气体的压力不变，则其体积与绝对温度成正比。
句型266：assuming（that）引出的条件状语从句
例句：Assuming that you are right, we'll make a great deal ofmoney from the project.
【★】：假定你是正确的，那我们将会从这项工程中赚得许多钱。
【句型点拨】：边际从属连词assuming（that）的意思是“如果”、“估计”，它表示在无确切的证明之前，假设某事是真的，其真实性有待证明。
You have brains, talent and a brilliant set of teachers so, assuming you are willing to work hard, I see a great future waiting for you all.
★你们有头脑、才华和一群优秀的老师，所以，假如你们愿意努力学习，我看到光明的未来在等候着大家。
Assuming that I see him, what shall I tell him？
★假如我见到他，我如何跟他讲呢？
Assuming that he is innocent, he must be set free.
★假如他是无罪的，就必须释放他。
句型267：once引出的条件状语从句
例句：Once the principal contradiction is grasped, all problems will be readily solved.
【★】：一旦抓住了主要矛盾，一切问题就迎刃而解。
【句型点拨】：once引出条件状语从句时，其意思是“一旦”、“一经”，它强调只要某个动作一发生，另一动作就会接着发生。
Once one loses self-confidence, he can never expect to be successful.
★一个人一旦失去了自信心，就甭想获得成功。
Once she starts talking, there is no stopping her.
★她一旦打开话匣子，就说个没完。
Once you've been to Iceland you'll understand why I like it so much.
★一旦你去过冰岛，你就会懂得我为什么这么喜欢它。
Remember that you won't be able to cancel the contract once you've signed.
★记住你一旦签字就不能取消合同。
The research is so designed that once begun nothing can be done to change it.
★研究是这样构思的，如果开始了，就不能进行任何更改。
句型268：介词with或without表示的条件意义
例句：With the courage to pursue them, all our dreams can come true.
【★】：有勇气去追求，我们的一切梦想都能实现。
【句型点拨】：某些介词，如with, without等构成的短语，表示“如果某事发生或存在，就……”、“如果某事没有发生或不存在，就……”的意思时，其意义相当于条件状语从句，表示一种假设，引导出真实条件，这种条件句中的谓语都用陈述语气。
"With support from the trade union, we should win the election," said Phil.
★费尔说：“有工会的支持，我们一定会赢得这次选举。”
With a change in our thoughts, we can change the world.
★改变我们自己的思维，我们就能够改变世界。
Without a large vocabulary, you can't expect to gain a good command of the English language.
★不尽力提高词汇量，你就不要期望掌握好英语。
Without education and money, he is powerless.
★没有受过教育也没有钱，他就没有权。
Without first-hand knowledge of the Middle East, you can hardly write an objective report about the situation in the area.
★没有中东的第一手资料，你几乎不可能写一篇客观的关于那一地区的形势报道。
Without water, air and sun, we couldn't live on the world.
★没有水、空气和阳光，我们就不可能活在这个世界上。
With steady wages, he would be able to feed himself and help his family.
★有稳定的收入，他一定能够养活自己并帮助养家。
With the help of a bank, we would be able to expand our business.
★有任何一家银行的帮助，我们就一定能够扩大我们的业务。
With the will to win, you would have achieved half your success.
★有取胜的意志，你已实现了成功的一半。
Without schooling, children grew up in ignorance.
★不上学，孩子们就会在愚昧中长大。
句型269：介词but for表示的条件含义
例句：But for the storm, the ship would have reached its destination on time.
【★】：要不是暴风雨，这条船一定会按时达到它的目的地的。
【句型点拨】：由but for（如果不是，要不是）引起的虚拟条件是对已经发生的事情作一种假设，句子的谓语常常用“情态动词＋完成时”的形式。
But for the flood, the ship would have reached its destination on time.
★如果不是这场洪水，这条船一定会按时达到它的目的地的。
But for the English examination I would have gone to the concert last Sunday.
★如果不是这次英语考试，上周星期天我一定会去音乐会的。
The storm delayed us. But for the storm we would have been in time.
★暴风雨阻挡了我们。如果不是暴风雨，我们会准时的。
But for his courage, the battle would have been lost.
★如果不是他的勇气，这场战斗一定会失败。
He might have been killed but for the arrival of the police.
★如果不是警察赶到，他可能就被杀死了。
句型270：“祈使句／名词词组＋and＋句子”表示的条件含义
例句：Hold a picture of yourself in your mind's eye, and you will be drawn toward it.
【★】：在你的心目中树立起一个你自己的形象，这样，你就会向这个形象靠拢。
【句型点拨】：“祈使句／名词词组＋and＋句子”表示条件含义时，在意思上相当于“if从句＋主句”。
Picture yourself vividly as defeated, and that alone will make victory impossible.
★倘使你把自己惟妙惟肖地想象成一个失败者，单这一点就会使胜利化为泡影。
Picture yourself as winning, and that will contribute immeasurably to success.
★你若把自己想象成一个胜利者，这将对你的成功起到不可估量的作用。
Do not picture yourself as anything, and you will drift.
★如果你心目中没有一个确立的形象，你就会随波逐流。
Please sit down for a few moments, and I'll tell the manager you're here.
★请坐下等一会儿，我去告诉经理你到了。
Drop a stone into a smooth lake, and the surface will be covered with circular waves moving outward from the centre.
★向平静的湖里投入一块石头，湖面出现从中心向外扩散的圆圈。
Bring the flowers into a warn room, and they'll soon open.
★把花带进一个温暖的房间，它们会很快开放。
Arrive late once again, and you're fired.
★再迟到，你将被开除。
Five minutes earlier, and you could have caught the last train.
★早5分钟，你就能够赶上最后一趟火车。
Give him an inch and he will take a mile.
★得寸进尺。
Another two days and I will finish the book.
★再给我两天，我就看完了这本书了。
句型271：“祈使句／名词词组＋or＋句子”表示的条件含义
例句：Wear your coat, or you will catch cold.
【★】：穿上你的大衣，不然你会感冒的。
【句型点拨】：“祈使句／名词词组＋or＋句子”表示条件含义时，在意思上相当于“unless或if not从句＋主句”。此时，句子表示了否定的含义。or后可以使用else。
Hurry up, or you'll be late.
★快点，否则你会迟到的。
Sleep now or else you'll never wake up tomorrow.
★现在就睡，要不然明天就会起不来。
Run for your life at five o'clock, or they will trample you to death.
★一到5点就逃命，否则它们会把你踩死的。
Write it down, or you'll forget it.
★写下来，否则你会忘的。
Work hard, or you won't be able to pass your examination.
★努力学习，否则你无法通过考试。