高中英语北师大版Uint4Cyberspace 优秀作品

英语条件句及其表达方式详解英语中的条件句种类很多,可用来表达建议、想法、结果和趋势等，其出现频率很高。在英语学习中，正确理解和抓住说话者所要表达的真实意图至为重要。下面介绍几种条件句及其不同的表达方式。

一、不同的条件句

1．真实条件句(realconditions)。用于陈述句，表假设的情况可能发生，其表达的意思直接而明显。

Ifhecomes,Ishallbesurprised.

Ifyouareenjoyingtheparty,don’tgohomeyet.

Ifyouhavedoneyourhomework,giveittome.

2．非真实条件句(unrealconditions)。非真实条件句分为三种情况：(1)与现在情况不符,(2)与过去情况不符,（3)与将来情况不符。非真实条件句是建立在与事实相反，或很难成为现实的假设基础上，其表达的意思是间接而含蓄的，表示假设的或实际可能性不大的情况。

Ifyouateless,youwouldloseweight.(可惜现在并未少吃)

Ifyouhadtakenanumbrella,youwouldn’thavebeensowet.（可惜那时没带伞）

Whatwouldyoudoifwarweretobreakout?(好在战争并不会爆发)

3．虚拟条件句（subjunctiveconditions)。虚拟条件句的从句部分如果含有were,should或had,可将if省略，再把这些词移到从句句首,实行倒装，构成不出现条件词的虚拟条件句。

Weretheyherenow,theycouldhelpus.

Hadyoucomeearlier,youwouldhavemethim.

Shoulditrain,cropswouldbesaved.

4．混合条件句(compositeconditions)，也叫错综时间条件句。即主句和从句的时态不相同，动作发生在不同的时间，主、从句谓语的虚拟语气形式因时间不同而不同。

IfJohnsonhadn’tbeenwarnedofthedangerlastnight,hewouldn’tdoeverythingsocarefully.

Ifithadrainedlastnight,itwouldbecoldtoday.

HadPaulreceivedsixmorevotesinthelastelection,hewouldbeourchairmannow.

5．含蓄虚拟条件句(complicitconditions),即条件句的简略形式。含蓄虚拟条件句指句中没有明显的虚拟条件句，而是利用其他手段(词汇手段、句子结构、上下文等)来暗示存在虚拟条件。

Wecouldhavedonebetterundermorefavorableconditions.

Butforhishelp,Ishouldn’thavesucceeded.Intheabsenceofmathematics,sciencewouldnotexist.

Marycouldn’thavereceivedmyletter,otherwise,shewouldhaverepliedbeforenow.

6．开放式条件句（openconditions)。即省略should的条件句。

Ifanypersonbeguiltyofacrime,hewouldbeprosecuted.

Whethersheberightorwrong,shewillhavemyunansweringsupport.

二、条件句的表达方式

1．用连词表达条件。最常见的连词有if,unless,aslongas,onlyif,or,but,otherwise等。

Ifitweren’tforhim,wewouldhavegoneastray.

Ifyouwanttobeextracautious,askyourcreditcardcompanytoissueyouaonetime-usecreditcard.

Youmayborrowmybooksolongasyoukeepitclean.

Imighthavegivenyoumorehelp,butIwasbusy.

Onlyiftheredlightcomesonisthereanydangerahead.

2．用非谓语动词形式表达条件

（1）V-ing/V-ed/V-baseform+that(clause)表达条件

Assumingthatasite’ssecure,yourcreditcardisthesafestwaytopay.

Supposing/Supposethatitrains,wecantakeshelterinthestation.

GiventhatIhavethemeansenough,I’llmaketheattempt.

Granted/Grantingthatheisnotbrilliant,heatleastworkshard.

(2)分词及独立主格结构表达条件

Havingknownintime,wemighthavepreventedtheaccident.

Borntendaysearlier,theboycouldhaveseenhislatefather.

Allthingsconsidered,thepricewouldbereasonable.

(3)动词不定式表达条件

Shewouldbestupidnottoaccepthisinvitation.

Itwouldbeamistakenottoadoptacorrectattitudetowardsothers’criticism.

TohearhimspeakFrench,youwouldtakehimforanEnglishman.

3．介词短语及介词短语+从句表达条件

I’llletyougoonconditionthatyouneverwastemoney.Youshouldinsureyourhouseincasethere’safire.

类似的结构还有forfearthat/of,inorderthat,without,butthat/for...

Butforthestorm,weshouldhavearrivedearlier.

Wecouldhavedonebetterundermorefavorableconditions.

4．定语从句表达条件

Amanwhostoppeddrinkingwaterwouldbedeadinabout7days.

Anyonewhohadbeeninyourpositionwouldhavedonethesame.

Anation,whichstoppedworking,wouldbedeadinafortnight.

5．助动词放句首表达条件

Shouldanyvisitorscome,Iwould/willsayyouarenotin.

Hadweenoughtime,thingswouldbeeasy.

HadIknownaboutit,Iwouldhavetoldyou.

6．形容词和副词的比较级形式表达条件

Amoreresponsiblepersonwouldn’thavelefttheworkhalfdone.

Alessconscientiousmanwouldn’thavetriedsohardtogetthejobdone.

7．祈使句+and或or引出的陈述句表达条件

Dothatagainandyou’llbeintrouble.

Givehimaninch,andhe’lltakeafoot.

Gobytrainandyou’llgettheremorequickly.

Takecareoryou’llfall.

Don’teatsomuchchocolateoryou’llfeelsick.

Hide,orelsehe’llcatchyou.

Doasyouaretold,otherwiseyou’llfeelsorry.

8．在正式文体中，谓语可用动词原形表达条件

Godblessyou!

Allmagnetsbehavethesame,betheylargeorsmall.

She’llbesixteenyearsold,comeMay.

Ifthatbeso,weshalltakeactionatonce.

9．情态动词的完成式表达条件

Ishouldhavecalledtomakeanairlinereservation,butIdidn’t.