今天北京环球教育王洪亮老师跟大家分享一个老生常谈的知识点，什么叫做条件状语从句呢？

　　通俗来讲，往往由引导词 if 或 unless 引导的状语从句叫做条件状语从句。在英文中，条件是指某一件事情实现之后，其它事情才能发生，通常译作“假如”。在雅思写作中，条件状语从句十分好用，拿过来就能用，可以起到很好的突出强调作用。

　　一提到条件句，很多同学马上就会想用if来引导。首先，我们一起来看以下七个句子：

　　Part A：

　　1.You can borrow my dictionary if you return it before you go home.

　　2.You cannot go to university if you do not have good grades.

　　3.Pollution will get worse if we continue to live in a throwaway society.

　　4.Many developed countries are willing to waive the Third World debt if the money is reinvested in education and medicine.

　　5.Some countries will never be able to rectify their deficits even if they work hard.

　　6.Computers are difficult things to understand, even if you read a lot of books about them.

　　7.Crime is a problem, even if you go to relatively safe countries.

　　这些句子都是由if 引导的条件句（ even if 可以是条件也可以是让步状语从句），这些句子固然很好，但是不是有些千篇一律呢？

　　条件状语从句不仅仅限于if，下面给大家介绍一些可以替换if 的方式。我们分别用以下短语来替换上面七句话中的if ：

　　providing that （假如 ） / unless (除非） / as long as （只要） / on condition that （ 如果， 条件是 ）/ no matter how （不管怎样）/ however many （ 无论多少）/ wherever  （无论什么地方）

　　第一句话可以直接用providing that ( 也可以用provided that ) 来替换if

　　1.You can borrow my dictionary providing that you return it before you go home.

　　第二句话可以把if not 换成unless

　　2.You cannot go to university unless you have good grades.

　　第三句话可以直接用as long as 替换if

　　3.Pollution will get worse as long as we continue to live in a throwaway society.

　　第四句话可以直接用on condition that 替换if

　　4.Many developed countries are willing to waive the Third World debt on condition that the money is reinvested in education and medicine.

　　第五句话用no matter how 直接替代if

　　5.Some countries will never be able to rectify their deficits even if they work hard.

　　第六句话用however many 直接替代even if

　　6.Computers are difficult things to understand, however many books you read about them.

　　第七句话用wherever 直接替代even if及后面的内容，改写为

　　7.Crime is a problem, wherever you go.

　　Part B：如果我们强调的重点是条件里的内容，那么我们可以把条件句放在句子的前面。现在试着把刚刚七个句子的强调内容提前：

　　1.Providing that you return it before you go home, you can bor-row my dictionary.

　　2.Unless you have good grades, you cannot go to university.

　　3.As long as we continue to live in a throwaway society, pollu-tion will get worse.

　　4.On condition that the money is reinvested in education and medicine, many developed countries are willing to waive the Third World debt.

　　5.No matter how hard they work, some countries will never be able to rectify their deficits.

　　6.However many books you read about them, computers are difficult things to understand.

　　7.Wherever you go, crime is a problem.

　　Part C：练习

　　现在到大家自由发挥的时间了，大家根据上面七个短语，来试着补充以下句子 ：

　　1.British universities will accept students from abroad __________

　　2.Working for a large company can be a fulfilling experience ____

　　3.Most banks are happy to lend customers money _____________

　　4.The government will reduce income tax ____________________

　　5.The environment situation will continue to worsen ____________

　　6.There will always be long waiting lists at our hospitals ________

　　7.Traveling helps you understand more about the world around you ______

　　Part D：此外，一些名词也可以表示条件，比如prerequisites ( n 前提，先决条件 ）  conditions ( n  条件 ） re-quirement  ( n 要求，条件 ）

　　我们一起来看以下三句话，来进行填空练习

　　1.Being able to drive is one of the _____ of the job of salesmen. （prerequisites)

　　2.Before you accept a job, it is important that you agree with the ______ of the contract.  ( conditions )

　　3.It is a _____ of the university that you attend an interview.   ( requirement )

　　Part E：if 除了可以表示条件外，还可以表示虚拟。条件可以是事实，但是虚拟表示与事实相反，不可能实现。虚拟语气有三种基本类型：与现在事实相反，与过去事实相反，与将来事实相反。

　　这三种情况所对应的句子结构和时态是不同的：

　　1.与现在事实相反：if + 一般过去时，主语 + would + 动词原形

　　例句：如果我是你，我就会接受他的建议

　　If i were you, I would accept his suggestions.

　　2.与过去事实相反：if + 过去完成时 (had done)，主语 + would + have done

　　例句：如果你昨天在这里，就能见到他了

　　If you had been here yesterday, you would have seen her.

　　3.与将来事实相反：if +一般过去时，主语+would +动词原形

　　例句：如果太阳不见了，你就会赢得大奖

　　If the sun were to disappear, you would win the jackpot.

　　所以我们看，其实条件状语从句可以有很多种不同的表达，大家可以在平时练习的时候变化自己的表达方式，丰富自己的文章。