If和whether的区别(含讲解+习题+答案)(可编辑修改word版)

1、If和whether的区别if和whether都可译为"是否"，二者引导宾语从句时通常可以互相替换，口语中多用if代替whether.例如：Askif/whetherheplanstocometothemeeting.而以下几种情况中,只能用whether:1. 强调两方面的选择,特别是句中有ornot时如：Letmeknowwhetheryoucancomeornot.2. 宾语从句前置时.如：Whetherthisistrue,Ican'tsay.3. 引导主语、表语、同位语从句时.如：Whetherthefootballgamewillbeplayeddepe

2、ndsontheweather.(主语从句)Thequestioniswhetherhecandoit.(表语从句)Thequestionwhetherweshouldgowiththemmustbedecidedatonce.(同位语从句)4. 在介词之后作介词的宾语时.如：Ihaven'tsettledthequestionofwhetherI'llgobackhome.5. 在不定式前与不定式一起组成词组时.如：Whethertogoorstayisstillaquestion.6. 在discuss,decide等动词后作宾语时.如：Wediscussedwhether

3、weshouldgotherebyplane.值得注意的是：if还可以引导条件状语从句,是"假如；如果"之意,而whether可以引导让步状语从句,是"不管；无论"之意.如：Ifyouaskhim,hewillhelpyou.Ishallgo,whetheryoucomewithmeorstayathome.一、if或whether引导宾语从句时,作“是否”讲，常放在动词ask、see、say、know和findout等后面一般情况下，两者常可换用,在口语中多用if.如:例1Nobodyknowswhether(if)itwillraintomorrow

4、.没有人知道明天是否下雨.例2Lucyaskedwhether(if)theyhadacottonsweater.露西问他们是否有棉制的羊毛衣.二、if或whether引导宾语从句时，要注意三个方面,即连词、语序和时态.1 if或whether不能和that或其它连词(副词)同时使用，也不能省去如：例3我不知道他今天是否会来.误Idon'tknowthatif(whether)hewillcomeheretoday.正Idon'tknowif(whether)hewillcomeheretoday.例4他走过来看看猫是否出了毛病.误Hecametoseewhatif(wheth

5、er)therewaswrongwithhiscat.正Hecametoseeif(whether)therewaswrongwithhiscat.2 if或whether引导的宾语从句时，虽具有疑问意义,但从句语序应用陈述句语序如：例5Didyouknowthewaytothehospital?Theoldwomanaskedme.Theoldwomanaskedme.if(whether)Iknewthewaytothehospital.老妇人问我是否知道去医院的路.3if或whether引导的宾语从句应和主句的时态保持一致.即主句为一般现在时,从句用任一种时态；主句为一般过去时,从句则用

6、过去时中的任一种时态.如：例6Idon'tknowif(whether)hehascomehere.我不知道他是否来过这儿.例7Tomaskedif(whether)Ihadreadthebook.汤姆问我是否看过这本书.三、if和whether的区别：1 在动词不定式之前只能用whether.如：例8Ican'tdecidewhethertostay.我不能决定是否留下.2 在whetherornot的固定搭配中.如：例9Iwanttoknowwhetherit'sgoodnewsornot.我想知道是否是好消息.3在介词后,只能用whether.如：例10Hisfa

7、therisworriedaboutwhetherhelosehiswork.他的父亲担心是否会失去工作.4宾语从句放在句首表示强调时,只能用whether.如：例11Whethertheycanfinishtheworkontimeisstillaproblem.他们是否能准时完成这项工作还是个问题.5用if会引起歧义时，只用whether.如：例12Couldyoutellmeifyouknowtheanswer?这句话有两种意思：“你能告诉我是否知道答案吗?”或“如果你知道答案,请告诉我,好吗?”.如用whether可避免歧义.if和whether专题1) Idon'tcarey

8、ourcarbreaksdownornot.2) Thisdependsuponwearedeterminedtodoit.3) Itdependsonheisready.4) Iamnotinterestedinyou'llcomeornot.5) Wehaven'tsettledthequestionofwe'llrenewoursuppliesofcoalforfactory.6) Hedoesn'tknowtostayornot.7) IamnotsureI'llhavetimetogowithyou.8) Shedoesn'tknowt

9、ogetmarriednoworwait.9) Idon'tknowornottheywillcomeforourhelp.10) Wediscussedweshouldmakeachangeinourplan.11) Heconsideredheshouldn'ttellherthesecret.Itisunknownhewillcome.Idon'tknowtheywillcometohelpus.Iamnotcertainthetrainwillarriveontime.thenewsistrueremainsaquestion.Whatwewanttoknowi

10、shewillcometospeaktoustomorrow.Thequestionistheycantakeouradvice.Letmeknowyoucan'tmeetmeatJacksonandThroopStreetsWednesdayafternoonattwoo'clock.Wewerediscussingweshoulddiscussthebusinesswiththem.Thequestionwe'llbuildanotherlecturehasn'tbeensettled.Thequestionhe'llcomeisunknown.Tellmeitisnotgoingtorain,please.Idon'tcarehedoesn'tshowup.Pleaseletmeknowyouintendtocome.12)13)14)15)16)17)18)19)20)21)22)23)24)25)LetmeknowhehasleftforShanghai.1) if/whether2) whether3) whether4) whether5) whether6) whether7) whethe