Question

宾语从句中WHETHER和IF的区别

Answer 1

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.

Answer 2

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.

Answer 3

1
在动词不定式之前只能用whether
。
2
在whether
……
or
not
的固定搭配中。
3
在介词后，只能用whether。
4宾语从句放在句首表示强调时，只能用whether
。
5用if会引起歧义时，只用whether。

Answer 4

宾语从句中引导词if和whether的区分方法