if 用法详解(九）if的替代表达

英语中的条件句(conditionals)分为四个等级：first，second，third和fourth。简单来说，这些条件句总体上是按条件的发生概率降序排列的：

Type 1:  百分百确定

People die if they don't eat.

不吃东西会死的。

Type 2:  一半可能

If I pass this exam, I’ll celebrate.

考试通过了的话，我要庆祝一下。

Type 3:  不真现实

If I lived by the sea, I would be lying on the beach right now.

我要是住海边，这会肯定在沙滩上躺平了。

Type 4:  遗憾史实

I would have helped you if you had asked me.

你要是早开口，我本来会帮你的。

你可能会觉得条件句都是围绕if来做文章，但其实if的替代表达有很多，看一看具体有哪些。

1.真实条件

(1)when和if可替换，when在语义上显得更加频繁和有规律

When you heat water to 100 degrees Celsius, it boils.

如果把水加热到100摄氏度，它就会沸腾。

A strong link is found between two species when a predator sticks to one prey species.

当捕食者坚持一种猎物时，两个物种之间发现了很强的联系。

This is hard to achieve when, as is now the case in many big firms, a large proportion of staff are temporary contractors.

就像现在许多大公司的情况一样，很大一部分员工都是临时承包商，这是很难实现的。

Teamwork is most effective when team members share the same culture.

当团队成员共享相同的文化时，团队合作最为有效。

  (2) if表示确定条件时还有一个变体：

①祈使句+and+ ...will do...

Follow the doctor’s advice, and you’ll be well very soon.

听从医生的医嘱，你很快就会好起来的

Take the following steps when reading and you will be a good fast reader.

按下列步骤阅读，你会成为一个阅读速度快的好读者。

Opportunity goes and comes easily; Grasp it and you will find your life quite different.

机会来得快去得快，抓住它，你的人生就会大不一样。

The world is like a mirror: frown at it and it frowns at you; smile, and it smiles too.

世界犹如一面镜子：朝它皱眉它就朝你皱眉，朝它微笑它也朝你微笑。

Learn to turn negatives into positives, and you’ll do much better in life.

学会把消极因素转化为积极因素，今后在生活中你就能做得好得多。

Open your eyes, open your heart, and you will see that goodness is everywhere.

睁开你的双眼，打开你的心扉，你就会发现人生美好无处不在。

②祈使句部分改用“名词短语 ＋ and分句”  ：

(Make) one more effort, and you will succeed in your experiment.

如果你再努力一下，你试验就会成功。

(Give me )One more hour, and I'll get the work finished.

再有一小时，我就可以干完了。

A bit more effort, and the problem would be straightened out.

再稍加把劲，这个问题就解决了。

(Come)Ten minutes earlier, and we could have caught the train already, but now we’ll have to wait an hour for the next train.

早来十分钟,我们就能赶上火车了, 但是现在我们不得不等一个小时乘下一趟火车。

注：英语中有不少用“祈使句 ＋ and 分句”表达的谚语

Give him an inch and he will take a mile.

   得寸进尺。

Set a beggar on horseback and he’ll ride to the devil.

叫化子发财忘乎所以。/一夜暴富

Take care of the pence and the pounds will take care of themselves.

积少成多；小事注意，大事自成。

Grasp the nettle and it won’t sting you.

你不怕困难，困难就怕你；困难像弹簧，你硬它就软。

Tread on a worm and it will turn.

困兽犹斗；狗急跳墙。

Ask no questions and you’ll be told no lies.

少问就听不到假话。

Jest with an ass and he will flap you in the face with his tail.

跟愚人开玩笑，只会自讨没趣。

Give a fool rope enough, and he’ll hang himself.

放任傻子等于害他。

Keep a thing seven years and you will find a use for it .

蓄艾三年，必有其用。

2.    强调条件

1）as/so long as，provided/providing (that)，on condition (that):只要;如果;条件是

As long as they meet certain conditions , students can also apply for a loan.

只要符合某些条件，学生也可以申请贷款。

It does not matter how slowly you go as long as you do not stop.

只要你不停下来，你走得有多慢并不重要。

I'll lend you the money provided/providing (that) you pay me back next month.

只要你下个月还我钱，我就把钱借给你。

  Use of the bridge by bicycle riders is allowed , provided that they use the 

bicycle  path .

只要骑自行车的人使用自行车道，他们就可以使用这座桥。

  I believe that a change of decoration is alright , on condition that the colors on 

the walls match the furniture .

我认为，只要墙上的颜色与家具相配，改变一下装饰是可以的。

The government agreed to delay implementation of the new measures by a month, on condition that protesters stopped blocking the roads.

政府同意将新措施的实施推迟一个月，条件是抗议者停止封锁道路。

2）only if 只有，仅当

These pills are effective only if you take them every day . 

这些药只有每天服用才有效。

Two heads are better than one only if they contain different opinions.

只有当两个人有不同的意见时，他们才会比一个人的意见更好。

You can overcome anything if and only if you love something enough.

你可以克服任何困难，只要你足够爱一样东西。

3.无视条件

1）whether (or not)/no matter +疑问词/regardless of不管，无论…如何/是否

No matter who you are, no matter how strong you are, sooner or later, you’ll face circumstances beyond your control.

无论你是谁，不管你有多强大，迟早都会面临你无法控制的情况。

All people, regardless of whether they're athletes or not, should treat people the way that they want to be treated.

所有人，无论他们是否是运动员，都应该以希望被别人对待的方式对待他人。

In the past , a girl had to marry a man their parents chose for her , whether she liked it or 

not .

在过去，女孩必须嫁给父母为她选择的男人，不管她喜欢与否。

2) even if /though即便/哪怕                                  Even though things worked out between them , they would still divorce.

即使他们之间的问题解决了，他们还是会离婚。

Facebook will not reinstate Donald Trump's suspended account early even if he announces that he will run again for president in 2024.

     脸书不会提前恢复唐纳德特朗普被暂停的账户，即使他宣布在 2024 年再次竞选总统。

4.    除外条件

1)    unless (:if…not) 除非

Unless it rains, we'll go for a picnic by the river tomorrow.

除非下雨，我们明天去河边野餐。Try to avoid eating late at night ,and never take sleeping pills unless prescribed by a doctor.

尽量避免深夜进食，除非医生开具处方，否则不要服用安眠药。

2)without/but for/if it were not for/if it hadn't been for要不是，若非，如果没有

Without your help I would never have been able to solve my problems.

如果没有你的帮助，我永远不可能解决问题。

It would have been more difficult but for your support.

如果没有你的支持，事情会更加困难。

Without the atmosphere, Earth would be too cold to live on.

如果没有大气层，地球将会过于寒冷而无法生存。

If it weren't for water, no plant could grow. 

要是没有水植物就无法生长。

If it hadn't been for the doctor's care, I wouldn't have recovered so soon. 

要不是医生的照顾，我不会痊愈得这么快。

If it wasn’t for me you'd have married her two years ago. 

要不是因为我的原因，你两年前就会同她结婚了。（张道真《现代英语用法词典》）

If it wasn't for the main actress, Ellen Barkin, the plot would have fallen flat on its face. 

如果不是女主角埃伦·巴尔金的话，整个情节会非常失败。（《柯林斯高级英语词典》）

5. 想象条件：

(1)suppose / supposing 假设，假如，多放句首 

Suppose/supposing you won the lottery, what would you do? 

假设你中了彩票，你会怎么做？

Supposing he hadn't recognized us – he might never have spoken to us.

假设他没有认出我们——他可能永远不会跟我们说话。

(2)in case (of)以防

It is always a good idea to keep an emergency kit at sight , in case of emergency.

在紧急情况下，随身携带应急包总是一个好主意。

Elon Musk sold $6.9 billion worth of Tesla shares to raise funds in case he loses the legal battle with Twitter and is forced to buy the social media platform.

Elon Musk 出售了价值 69 亿美元的特斯拉股票以筹集资金，以防他在与 Twitter 的法律战中败诉并被迫购买这家社交媒体平台。

(3)in the event (of) 万一， 倘若

The roof of the cabin has been engineered to provide protection against head injuries in the event of a collision.

客舱的屋顶经过精心设计，可以在发生碰撞时防止头部受伤。

Airbags protect the driver in the event of a severe frontal impact.

汽车若遇到正面猛烈撞击，安全气囊可以保护驾车者。

  The doors can be manually operated in the event of fire.

发生火灾时,这些门可以手动控制.

In the event that you win a prize in the competition, the school will reward you.

如果你们在比赛中得了奖，学校会奖励你们。

In the event (that) the factory defaults on the debts,the bank will freeze its account. 

如果工厂拖欠债务，银行将冻结其帐户。

6. 反向条件

(1)otherwise否则

Be there on time, otherwise you'll create a bad impression.

要准时来，否则你会给人一个坏的印象。

Seize the chance, otherwise you'll regret it.

抓住这个机会，否则你会后悔的。
      You 'd better do it right away ; otherwise , you 'll never do it.

你最好马上做这件事，否则你永远不会做这件事。 

We're committed to the project. We wouldn't be here otherwise.

我们是全心全意投入这项工作的，否则我们就不会到这里来了。

Otherwise, the recreation of traditions would be artificial and empty, he said.

他说，否则，对传统的再现将是人为的、空洞的。

(2)or (else)要不然

It is raining. Don't forget to wear a raincoat, or else you will catch a cold.

下雨了, 出门别忘穿上雨披, 要不会淋感冒的。

Many foods must be refrigerated or else they will spoil.

许多食物必须冷冻,否则会变质。

Make haste, or ( else ) you'll be late.

快点, 要不然就来不及了。

He must have thought Jane was worth it or he wouldn't have wasted time on her, I suppose.

我想，他一定认为简值得他这么做，否则他不会在她身上浪费时间。

You can't walk out on the contract, or you could be taken to court.

你不可违反合同, 否则你会被起诉。

Don't jump the queue, or other people will not be pleased.

别插队, 否则别人会不高兴的。

It knows it must outrun the slowest deer, or it will starve to death.

它知道要快过最慢的鹿, 否则就会饿死。