【whether和if的区别】【whether和if的区别和用法】_英语_pf46044lz
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一、引导宾语从句,一般既可用whether也可用if.但
1 or not放在whether之后时,只能用whether不用if.
I don’t know whether or not he will come. 我不知道他是不是回来.
注1：如果or not放在whether所引导的从句句尾,则可以用if来替换.
I don’t know whether/if he will come or not.我不知道他是不是回来.
2 在强调任意选择时,用whether…or,此时不用if替换whether.
He asked me whether I wanted to go there by train or by bus.他问我是想乘火车还是坐公共汽车去那里.
注：whether和or一起还有“不管”之意,引导让步状语从句.
Whether he drives or takes the train, he will be here on time.不管开车来还是乘火车来,他都会准时到.
3 虽引导宾语从句,但为了强调宾语部分,也可把从句放在句首,此时只用whether不用if.
Whether he will come I am not sure.他是不是来我拿不准.
4 从句作介词宾语时只用whether不用if.
It depends on whether it will be fine.那得看是不是晴天.
5 作discuss等动词的宾语时,用whether不用if.
We discussed whether we should close the shop.我们讨论是不是该关掉商店.
6 句子中有if引导的条件句,如再有表示“是否”的宾语从句,用whether不用if.
He asked me whether I’d move to New York if I got the job.他问我如果我得到那份工作是否会搬家到纽约.
7 容易产生歧义时用whether不用if来表示“是否”.
Please let me know if you need help. 如果你需要帮助请告诉我.或：请告诉我你是否需要帮助.对比：Please let me know if you need help.请告诉我你是否需要帮助.
8 如果宾语从句为否定句时,则只用if不用whether.
I don’t know if it won't rain tomorrow..我不知道明天是不是会下雨.
二、在引导主语从句、表语从句、同位语从句时一般用whether不用if.如：
⑴Whether it is true remains a question.(主语从句)那是不是真的还是个问题.
⑵The question is whether it is true.(表语从句)问题是是不是真的.
⑶We have a doubt whether it is true.(同位语从句) 我们怀疑那是不是真的.
注:whether引导主语从句放在主句之后时可用if来代替.
It is unclear whether/if he likes the present.他是不是喜欢那个礼物还不清楚.
三、用在动词不定式之前时用whether不用if.
I don’t know whether to go there at once. 我不知道是不是该立刻去那里.
其他同学给出的参考思路：
whether和if的区别
whether和if常用来引导宾语从句,一般可通用.
①I don't know whether/if they will come to help us. 我不知道他们是否来帮助我们。
②I am not sure whether/if I'll have time to go with you. 我很难说我们是否有时间跟你们一起去。
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互助这道作业题的同学还参与了下面的作业题
题1： 【whether和if在用法上有什么区别?最好举几个例子.】[英语科目]
whether和if的用法区别
whether与if作“是否”讲,在用法上有相同之处,也有不同之处.
一、相同之处.
1.whether和if都能引导宾语从句,常置于see,ask,learn,tell,wonder,doubt,find out等动词之后.
如：He asked me whether/is I could help him.I want to know whether/if he lives there.
2.whether和if都可用it作形式主语从句中.如：it's uncertain whether/if he'll come this evening.
3.在be uncertain/doubtful之后,常用whether引导宾语从句,有时也可以用if,如：We are uncertain whether/if Mary will come.
二、不同之处.
1.whether可置于句首引导主语从句,而if不能.如：___the 2000 Olympic Games will be in Beijing is not known yet.A.whether B.If C.Whether D.That 答案是C.
2.whether可用在介词之后,引导宾语从句,而If则不能.如：Success depends on whether we make evough effort.
3.whether可引导表语从句,if则不能.如：The puestion is whether it is not worthdoing.
4.在名词之后引导同位语从句时,用whether而不用if.如：The puestion whether the students answered correctly should be decided by the teacher.
5.whether后可接不定式,而if不能.如：Please tell us whether to go or stay here.
6.在有些动词（如discuss）之后,只能用whether,而不用if引导宾语从句.如：We discussed whether we should close the shop.
7.在引导否定概念in宾语从句时,只能用if,而不用whether.如：he asked me if I hadn't finished my work.
题2： whether,if的用法和区别如题[英语科目]
whether和if的用法区别
whether与if作“是否”讲,在用法上有相同之处,也有不同之处.
一、相同之处.
1.whether和if都能引导宾语从句,常置于see,ask,learn,tell,wonder,doubt,find out等动词之后.
如：He asked me whether/is I could help him.I want to know whether/if he lives there.
2.whether和if都可用it作形式主语从句中.如：it's uncertain whether/if he'll come this evening.
3.在be uncertain/doubtful之后,常用whether引导宾语从句,有时也可以用if,如：We are uncertain whether/if Mary will come.
二、不同之处.
1.whether可置于句首引导主语从句,而if不能.如：___the 2000 Olympic Games will be in Beijing is not known yet.A.whether B.If C.Whether D.That 答案是C.
2.whether可用在介词之后,引导宾语从句,而If则不能.如：Success depends on whether we make evough effort.
3.whether可引导表语从句,if则不能.如：The puestion is whether it is not worthdoing.
4.在名词之后引导同位语从句时,用whether而不用if.如：The puestion whether the students answered correctly should be decided by the teacher.
5.whether后可接不定式,而if不能.如：Please tell us whether to go or stay here.
6.在有些动词（如discuss）之后,只能用whether,而不用if引导宾语从句.如：We discussed whether we should close the shop.
7.在引导否定概念in宾语从句时,只能用if,而不用whether.如：he asked me if I hadn't finished my work.
题3： 【if和whether的用法和区别】[语文科目]
if是如果,whether是无论!if用于肯定句!whether用于否定句和一般疑问句
题4： 【if与whether在用法上有什么区别】[英语科目]
可以看看语法书:一、引导宾语从句,一般既可用whether也可用if.但 1 or not放在whether之后时,只能用whether不用if. I don’t know whether or not he will come.我不知道他是不是回来. 注1：如果or not放在...
题5： 【whether和if的用法区别哪个高手详细讲下?急】[英语科目]
whether和if都可以引导宾语从句,表示“是否”,在口语或间接引语中两者可以互换使用.如：
I wonder if / whether I can get some advice from you.
Ask him whether / if he can come.
但在有些情况下,whether和if的用法有一定区别.
1.whether引导的从句常可以与连词or或or not直接连用,而if一般不能.如：
正：Let me know whether you can come or not.
误：Let me know if you can come or not.
2.当宾语从句提到句首时,只能用whether引导,而不能用if.如：
正：Whether it is true or not,I can’t tell.
误：If it is true or not,I can’t tell.
3.whether可以引导带to的不定式,if则不能.如：
正：I don’t know whether to accept or refuse.
误：I don’t know if to accept or refuse.
4.whether及其引导的成分可放于介词之后,作介词的宾语,但if不能.如：
正：I worry about whether I hurt her feelings.
误：I worry about if I hurt her feelings.
5.whether可以引导从句,作主语、表语或同位语,而if不能.如：
正：It was uncertain whether he would come.
误：It was uncertain if he would come.
正：His first question was whether Tom had arrived yet.
误：His first question was if Tom had arrived yet.
正：We must consider the question whether we will take these measures.
误：We must consider the question if we will take these measures.