whether 和if 的用法

初三 Whether 和if 的用法
1.whether 和if 均可用来引导主语从句，但if 引导的从句不能位于句首。

如： Whether they win or lose is all the same to me. 他们是赢是输於我都一样.（此时whether 不能换作if ） It's doubtful whether there'll be any seats left. 说不上还有没有空座位了. (此句whether 能换作if)
2.whether 和if 均可用来引导宾语从句。

如：①I don't know whether/if I will be able to come.我不知道我是否能来.
②She asked me whether/if I was interested in working for her.她问我是否有兴趣为她工作。

③We'll be told tomorrow whether we should take the exam or not.我们明天才知道是不是应该参加考试.
④I asked him whether he had done all the work himself or whether he had had any assistance. 我问他这些工作都是他自己做的还是别人帮他做的.
( 注意: 在两个供选择的从句之间若用or 字, 则须重复whether 一字. )
注: ⑴当强调宾语从句并将其提前时只能用whether 。

如:Whether I'll have time to go with you I am not sure.我很难说我们是否有时间跟你们一起去。

⑵ 从句作介词宾语时只用whether 不用if 。

如:She was undecided about whether she should accept his offer.她拿不定主意应该不应该接受他的好意 ⑶ 当whether 和or not 连用时，只用whether 不用if 。

当or not 放在whether 引导的从句句尾，则可以 用if 来替换。

如: I don’t know whether or not he will come.我不知道他是不是回来。

I'll be happy whether/if I get the job or not 我能不能得到那份工作都一样高兴 ⑷ 当whether 和or 连用表示明确的选择时，只用whether 不用if 。

如: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。

He hesitated about whether he should drive or take the train.他开车去还是坐火车去, 犹豫不决
注:whether 和or 连用还可以引导让步状语从句,此时也不用if 。

如：We'll go on with the work, whether we can find the necessary tools or not.
不管我们能否找到所需的工具,我们要把这件工作做下去。

Whether or not it rains / Whether it rains or not, we're playing football on Saturday. 无论下不下雨, 我们星期六一定踢足球.
⑸ 动词discuss ，decide,consider 等后习惯上也常用Whether 引导从句，不用if 。

They discussed whether they should leave at once.
他们讨论了是否应该马上离开。

We discussed whether the house should be sold.
我们讨论了这房子是否应卖掉。

3.表语从句用whether 引导不用if.
如:①The doubt was whether you had broken the beautiful vase. 疑问是你是否打坏了这只漂亮的花瓶。

4. 同位语从句用whether 引导不用if .
如:①The question whether we'll build another lecture building hasn't been settled. 是否要另建一幢教学楼的问题还未决定。

5. 在动词不定式之前，只能用whether ，不能用if 。

如:①The question is whether to go to Munich or Vienna. 问题是去慕尼黑还是去维也纳. ②She doesn't knows whether to get married now or wait. 是否现在结婚或是等待她不知道。

③We were wondering whether to go today or tomorrow. 我们弄不清是今天走还是明天走.
④I'm not sure whether to resign or stay on. 我拿不准主意是辞职还是留任.
强化练习：
1. The question has not been answered ____ Taiwan will be included on the Olympic tor ch relay route.
A ．that
B ．whether
C ．which
D ．if
2. You have not yet answered my question _____ I can join in the party tonight or no t.
A. whether
B. if
C. that
D. which
3．— I d like to invite you to a party this evening.
— Thank you, but _____ I’ll be free I m not sure at the mome nt. A. while B. if C. when D. whether 4．---What are you anxious about? ---___________
A. If we succeed
B.That we can succeed
C. Do we succeed
D.Whether we can s ucceed
5. Only when _____ the painting _____ decide ______the painting is worth buying. A. he sees, he can ,whether B. does he see, can he, if C. he sees, can he ,whether D. sees he, he can,that
6. _____ English is his favourite subject
A. I asked him if
B. I asked him that whether
C. I asked him that
D. I asked hi m which
7. _____ they’ll go to the Summer Palace ____ the weather.
A. If; depends on
B. Whether; depends upon
C. Whether; depended on
D. If; d epended upon
8.It isn’t quite _____ ______ he will be present at the meeting.
A. sure; whether
B. sure; if
C. certain; whether
D. certain; that 9. _____ the 2008 Olympic will be held in Beijing is not known yet. A. Whether B. If C. Whenever D. That
10. No one was sure _____ he would be asked to speak next year. A. when B. whether C. what D. how
11. It is still a question to us all _____ there is any living thing in some other places in the space.
A. whether
B. which
C. what
D. where 12. I doubt _____ he will come here on time. A. that B. whether C. when D. where 13. A. but whether C. but how 14. “What did he as A. That B. When C. Where
15. He treated all the people around him,______he knew or he didn't know,______.
A. if, friendly
C. if, in a friendly way
D. whether, in a friendly
way
A. if C. that D.不填
Answers: BADDC ABCAB ABADD B
由whether,if 引导的宾语从句
（一）由whether,if 引导的宾语从句由whether(if)引导的宾语从句，实际上是一般疑问句演变而来的。

意思是“是否”。

宾语从句要用陈述句语序。

一般说来，在宾语从句中whether与if可以互换使用，但在特殊情况下if与whether是不能互换的。

例句：I wonder whether(if) they will come to our party.
（二）只能用whether，不能用if引导的宾语从句
1.在带to的不定式前：We decided whether to walk there.
2.在介词的后面：I’m thinking of whether we should go to see the film.
3.直接与or not连用时
例句：I can’t say whether or not thet can come on time.
4.当强调宾语从句并将其提前时只能用whether。

如:Whether I'll have time to go with you I am not sure.我很难说我们是否有时间跟你们一
起去。

5.当whether和or 连用表示明确的选择时。

如: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。

6.动词discuss，decide,consider，sure等后习惯上也常用Whether引导从句，不用if。

They discussed whether they should leave at once.他们讨论了是否应该马上离开。

We discussed whether the house should be sold. 我们讨论了这房子是否应卖掉。

（三）其他只能用whether不能用if的情况
1.表语从句用whether引导不用if.
如:①The doubt was whether you had broken the beautiful vase. 疑问是你是否打坏了这只漂亮的花瓶。

2 同位语从句用whether引导不用if.
如: The question whether we'll build another lecture building hasn't been settled. 是否要另建一幢教学楼的问题还未决定。

3位于句首的主语从句只能用.whether。

如： Whether they win or lose is all the same to me. 他们是赢是输於我都一样.（此时whether不能换作if ）
It's doubtful whether there'll be any seats left. 说不上还有没有空座位了. (此句whether能换作if)
只能用if不能用whether引导的宾语从句
1.if引导条件状语从句，意为“如果”
例句：The students will go on a picnic if it is sunny.
2.if引导否定概念的宾语从句时
例句：He asked if I didn’t come to school yesterday.
3.引导状语从句even if（即使）和as if（好象）时
例句：He talks as if he has known all about it.
强化练习：
B1，We will go swimming ---------- it is fine tomorrow．A. while B. if C. when D. whether
A2. You have not yet answered my question _____ I can join in the party tonight or not.
A. whether
B. if
C. that
D. which
D3．— I d like to invite you to a party this evening.
—Thank you, but _____ I’ll be free I m not sure at the moment.
A. while
B. if
C. when
D. whether
D4．---What are you anxious about? ---___________
A. If we succeed
B.That we can succeed
C. Do we succeed
D.Whether we can succeed
C5. Only when ___ the painting ___decide ______the painting is worth buying.
A.he sees, he can ,whether
B. does he see, can he, if
C. he sees, can he ,whether
D. sees he, he can,that
A6. _____ English is his favourite subject
A. I asked him if
B. I asked him that whether th
C. I asked him that
D. I asked him which
B7. _____ they’ll go to the Summer Palace ____ the weather.
A.If; depends on
B. Whether; depends upon
C. Whether; depended on
D. If; depended upon
C8.It isn’t quite _____ ______ he will be present at the meeting. （it is 。

that 结构中只能有certain不能用sure）
A. sure; whether
B. sure; if
C. certain; whether
D. certain; that
B.9He asked me if I hadn't finished my homework．他问我是否没有完成作业。

A. while B. if
C. when
D. whether B10. No one was sure _____ he would be asked to speak next year. A. when B. whether C. what D. how
B11. I doubt _____ he will come here on time. A. that B. whether C. when D. where。