IB英语基础语法：“if”与“whether”的用法辨析

　　在IB课程准备学习阶段，不仅英语的单词量在逐渐增加，而且它的语法难度也是快速提升，今天，小编整理了IB语法“if”与“whether”的用法区别的内容，希望可以帮到大家。

　　相同点：

　　1、if或whether在宾语从句中有意义，不充当成分。这两个词是“是否”的意思，不能省略。

　　He asks me if / whether I have ever been to Beijing.

　　他问我是否去过北京。

　　She wanted to know whether I could pass the exam or not.

　　她想知道我是否通过了考试。

　　不同之处

　　1.whether可置于句首引导主语从句,if则不能

　　如：

　　Whetherthe 2000 Olympic Games will be in Beijing is not known.

　　Whetherthe football game will be played depends on the weather.

　　Whetherhe will come is still a question.

　　2. whether可引导表语从句 , if 则不能

　　如：

　　The questionis whetherit is not worth doing.

　　The questionis whetherhe can do it.

　　The questionis whetherwe should go on with the work.

　　3.whether可引导同位语从句时, if则不能

　　如：

　　The question whether the students answered correctly should be decided by the teacher.

　　The question whether we should go with them must be decided at once.

　　4.宾语从句置于句首表示强调时,用whether,不用 if

　　如：

　　Whether this is true, I can't say.

　　Whether he is single, I don't know.

　　5.在介词之后只能用whether引导宾语从句,而if 则不能

　　如：

　　Success dependson whetherwe make enough effort.

　　I haven't settled the questionof whetherI'll go back home.

　　It dependson whetherthe letter arrives in time.

　　I worryabout whetherI hurt her feelings.

　　6.在动词不定式之前只能用whether,而if不能

　　如：

　　Please tell uswhetherto goorstay here.

　　Whetherto goorstay is still a question.

　　I'm not surewhether tostay or leave.

　　I didn't knowwhether tolaughorto cry.

　　7.在某些动词（如 discuss ,decide ）之后,只能用whether,而不用 if引导宾语从句

　　如：

　　Wediscussed whetherweshouldclose the shop.（虚拟语气）

　　Wediscussed whetherweshouldgo there by plane.（虚拟语气）

　　Wediscussed whetherweshouldhold a meeting.（虚拟语气）

　　8.在引导否定概念宾语从句时,只能用if ,而不用whether

　　如：

　　He asked me if I hadn't finished my work.

　　注： doubt 否定句用 that 引导。因为 don't doubt意为相信,不怀疑, if 是否表示疑虑。

　　9.与or连用分别引导两个从句时,或强调两方面的选择,特别是句中有or not时用 whether ,不用 if

　　如 ：

　　I don't knowwhetherhe is wrong or she is wrong.

　　Let me knowwhetheryou can come or not.

　　I don' t knowwhetherhe will win or not.

　　I will write to youwhetheror not I can come

　　I will write to youwhetherI can come or not.

　　or若不是引导两个从句,而是连接两个词或短语,则也可用if ( 但不如用whether 常见 )。

　　如：

　　He didn't know if/whether we should write or phone.

　　10.用 if 会引起歧义或者句中已经有一个引导条件状语从句的if 时,用whether 。

　　11.if还可以引导条件状语从句,是“假如、如果”之意,而whether 还可以引导让步状语从句（在句中不充当成分）,是“不管、无论”之意。

　　如：

　　If you ask him, he will help you.

　　I shall go,whetheryou come with me or stay at home.

　　Whetherhe agrees or not, I shall do that.

　　（区别no matter what和whatever ,两者在句中充当成分。）

　　以上就是小编为大家整理的关于IB英语语法辨析之“if”与“whether”的用法区别，希望对大家有所帮助。更多ib课程适合什么人、ib都有哪些课程等问题可以咨询我们。