whether和if的区别.doc

引导宾语从句在引导宾语从句时，whether?和if?通可以互换，在ask,care,doub,know,learn,msee,tell,try,wonder等动词之后尤其如此。例如：I?don’t?know?if/whether?I?can?help?you.They?don’t?care?a?bit?whether?my?reports?are?good?or?bad..I?wonder?if?you?can?examine?him?now.(高一册第十四页)I?am?not?sure?if/whether?I’ll?have?time.但是，必须注意以下几点：　1）如果从句是否定结构，则用if不用whether.例如：　Well,think,and?see?if?the?most?religious?people?aren’t?those?who?fell?that?this?life?doesn’t?gice?them?all?they?want.好，你想，那最虔诚的宗教徒，是不是就是那此觉得这现实的人生没有完全满足自己欲望的人？　Dinner?was?almost?over?when?Dan,still?looking?hungry,grinned?and?asked?Dave?if?he?wasn’t?going?to?have?some?bread.晚饭快吃完的时候丹（他看上去还没吃饱）笑着问戴维还要不要吃些面包。??I?don’t?care?if?he?doesn’t?show?up?.他来不来我都不在乎。?　?Let?me?know?if?you?can’t?meet?me?at?Jackson?and?Throop?Streets?Wednesday?afternoon?at?two?o’clock.星期三下午奉告警方，你是否能在杰逊街和思鲁街的黑心角来跟我相会。（＜嘉莉妹妹＞＝当然，对某些句子，人们可能会有不同的理解。如上面最后两列中的if?也可理解为引导条件状语从句：　　他不来我也不在乎。如果　你在星期三下午二时不能和我在杰克逊街和思鲁街的黑心角相会，请通知我。但是，当doubt是还定式时，则不用whether或if，要改用that,因为句子本身已没有“怀疑”或选择之意。度比较：I?don’t?doubt?that?you?are?honest.我不怀疑你的诚实。She?never?doubt?for?a?moment?that?she?was?right.她对自己是正确的这一点从不怀疑。I?doubt?whether?it’s?true.I?doubt?if?that?was?what?he?wanted.2)宾语从句前置时只能用whether,如：Whether?he?lives?there,I?want?to?know.Whether?this?is?true?or?not?,I?can’t?say.Whether?we?can?relly?help?ypu?,I?don’t?know?yet?.我们是否真的能帮助你，我还不知道。　　3）在decide,dicuss等动词后，通常只跟whether引导的宾语从句。如：They?dicussed?whether?they?should?close?the?shop.他们痔疮了是不是该关掉商店。The?old?lady?has?not?decided?whether?she?will?live?with?her?daughter?in?the?countryside.????4)出现在介词后面的宾语从句只能用whether引导，如：The?teacher?worried?about?whether?he?had?hurt?the?girl’s?feelings.老师担心他是否伤害了女孩的感情。It?all?depends?on?whether?she?likes?the?boss?or?not?.一切都取决于她是否喜欢这位上司。It?depends?on?whether?the?crystal?can?emit?a?powerful?beam?of?light.这取决于晶体是否会发射出一束强光。　　5）句中含有引导条件状语从句的if?时，用whether?不用if，如：Bill?asked?whether?,if?I?got?the?job,I’d?move?to?York.比尔问如果我得到这份工作是否还要迁到约克。　　6）在现代英语中似乎有一种趋势，即说话人期望得到或估计会得到肯定答复时常用if?，而在对答复时的肯定与否