If和whether的区别含讲解+习题+答案

1、If和whet her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： Ask if/whether he plans to come to the meeting. 几种情况中,只能用 whether:1. 强调两方面的选择，特别是句中有 or not 时.如：Let me know whether you can come or not.2. 宾语从句前置时.如：Whether this is true, I cant say.3. 引导主语、表语、同位语从句时.如：Whether the football g

2、ame will be played depe nds on the weather.句)The questi on is whether he can do it.(表语从句)The questi on whether we should go with them must be decided at once. 位语从句)4.在介词之后作介词的宾语时.如:I havent settled the question of whether Ill go back home.5.在不定式前与不定式一起组成词组时.如：Whether to go or stay is still a questi

3、on.6.在 discuss, decide 等动词后作宾语时.女口:We discussed whether we should go there by pla ne.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:If you ask him, he will help you.I shall go, whether you come with me or stay at home.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 find out等后面

4、.一般情况下，两者常可换用，在口语中多用 if.如：例 1 Nobody kn ows whether (if) it will rain tomorrow.没有人知道明天是否下雨.例 2 Lucy asked whether (if) they had a cotton sweater .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I don t know that if(whether) he w

5、ill come here today . 正I don t know if(whether)he will come here today .例 4 他走过来看看猫是否出了毛病.误He came to see what if (whether) there was wrong with his cat .正He came to see if (whether) there was wrong with his cat .2if 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 5 Didyou know the way to the hospital

6、? The old woman asked me .The old woma n asked me .if (whether) I knew the way to the hospital .老女日而以下(主语从(同人冋我是否知道去医院的路3 if 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，从句则用过去时中的任一种时态如：例 6 I don t know if (whether) he has come here .我不知道他是否来过这儿 例 7 Tom asked if (whether) I had read the

7、 book .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 .女口：例 8 I can t decide whether to stay.我不能决定是否留下2 在 whether . or not 的固定搭配中如：例 9 I want to know whether it s good news or not 我想知道是否是好消息 3 在介词后,只能用 whether.女口：例 10 His father is worried about whether he lose his work .他的父亲担心是否会失去工作4 宾语从句放在句首

8、表示强调时,只能用 whether 女口：例 11 Whether they can finish the work on time is still a problem .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.女口：例 12 Could you tell me if you know the an swer ?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 和口 whether 专题1)I dont care_ your car breaks dow n or not

9、.2)This depe nds upon_ we are determ ined to do it.3)It depe nds on_he is ready.4)I am not in terested in_youll come or not.5)We have nt settled the questi on of_ well renew our suppliesof coal for factory.6)He does nt know_to stay or not.7)I am not sure_ ril have time to go with you.8)She does nt k

10、now_to get married now or wait.9)I dont know_ or not they will come for our help.10) We discussed_ we should make a change in our plan.11) He considered_he should nt tell her the secret.12) It is unknown_ he will come.13) I dont know_ they will come to help us.14) I am not certain_ the train will ar

11、rive on time.15) _the n ews is true rema ins a questi on.16) What we want to know is _ he will come to speak to ustomorrow.17) The question is_they can take our advice.18) Let me know_ you can t meet me at Jacks on and ThroopStreets Wednesday afternoon at two o clock.19) We were discuss ing _ we sho

12、uld discuss the bus in esswiththem.20) The questi on_ well build ano ther lecture has nt bee n settled.21) The question_hell come is unknown.22) Tell me_it is not going to rain, please.23) I don t care_ he doesn t show up.24) Please let me know_ you intend to come.25) Let me know_ he has left for Shanghai.1)if/whether2)whether3)whether4)whether5)