whether 和 if 的区别与习题.doc

《whether 和 if 的区别与习题.doc》由会员分享，可在线阅读，更多相关《whether 和 if 的区别与习题.doc（5页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、whether 和 if 的区别与习题whether 和 if 的区别与习题一、二者区别 1）引导宾语从句时通常可以互相替换, 口语中多用 if 代替 whether. 常放在动词ask 、see 、say 、know和find out 等后面. Nobody knows whether (if) it will rain tomorrow. 没有人知道明天是否下雨. Lucy asked whether (if) they had a cotton sweater .露西问他们是否有棉制的羊毛衣. Ask if/whether she wou

2、ld take the apple. 2） if 引导条件状语从句, 假如；如果 ， 而whether引导让步状语从句, 不管；无论 ； If you ask him, he will help you. I shall go, whether you come with me or stay at home. 二、只能用whether的情况： 1. 强调两方面的选择, 特别是whether or not连用时. He didn t say whether or not he ll be staying here. Let

3、me know whether you can come or not. 但是，当or not 句子后置，也可以用if . (伦道夫. 夸克，1998朗文英语语法大全) He didn t say if he ll be staying here or not. 2. 宾语从句前置时. Whether this is true, I can t say. 3. 引导主语、表语、同位语从句时. Whether the football game will be played depends on the weather. （主语从句）&

4、nbsp;The question is whether he can do it. （表语从句） The question whether we should go with them must be decided at once. （同位语从句） 4. 在介词之后作介词的宾语时。 I haven t settled the question of whether I ll go back home. 5. 在不定式前与不定式一起组成词组时. Whether to go or stay is still a question. 6

5、. 在discuss, decide 等动词后作宾语时. We discussed whether we should go there by plane. if 可以用来引导一个否定的宾语从句, whether则不能用来引导否定的宾语从句, 因为它表示正反两方面的选择意义比较强. Tell me if it is not going to rain,please. 请告诉我明天是否不会下雨. He considered if he shouldn t tell her the secret. 他考虑他是否不该告诉她这个秘密.&nbs

6、p;三、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； 我不知道他今天是否会来. 误 I don t know that if(whether) he will come here today . 正 I don t know if(whether) he will come here today . 他走过来看看猫是否出了毛病. 误 He came to see what if (whether) there was wr

7、ong with his cat . 正 He came to see if (whether) there was wrong with his cat . 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； Did you know the way to the hospital ? The old woman asked me . The old woman asked me if (whether) I knew the way to the hospital . 老妇人问我是否知道去医院的路.&nb

8、sp;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： I don t know if (whether) he has come here . 我不知道他是否来过这儿. Tom asked if (whether) I had read the book . 汤姆问我是否看过这本书 . 四、总结 1） 在动词不定式之前只能用whether .如： I can t decide whether to stay. 我不能决定是否留下.&n

9、bsp;2） 在whether or not 的固定搭配中.如： 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.如： His father is worried about whether he lose his work . 他的父亲担心是否会失去工作. 4）宾语从句放在句首表示强调时,只能用whether .如： Whether they can finish the work on time is still a problem

10、. 他们是否能准时完成这项工作还是个问题. 5）凡可能引起歧义的地方，有时为了区别是疑问分句还是条件句，有必要用语调或标点来分隔。 Could you tell me if you know the answer ? 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.疑问分句： I ll tell you later if/whether I can find the time. 条件句： I ll tell you later, if I can find the time = If I can find the time, I ll tell you later. 所以，用 if 会引起歧义时, 不妨只用whether。 第 5 页 共 5 页