whether 和if区别
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.
强化练习：
1. The question has not been answered ____ Taiwan will be included on the Olympic
torch 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 not.
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 moment.
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 succeed
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 him 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; depended upon
8.It isn’t quite _____ ______ he will be prese nt 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 ask you?” “_____ I
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。