whether和if均可用来引导宾语从句，表示“是否”，如： don't know whether/if I will be able to come.我不知道我是否能来. She asked me whether/if I was interested in working for her.她问我是否有兴趣为她工作。 但也有差别： 1、 whether可以与or 或or not连用，而if不可以，如： He wondered whether he should wait or go . I don’t know whether he will come. or not。 2 介词之后用 whether , 不用 if . It depends on whether you will agree . 3 不定式前面用 whether 不用 if . I wonder whether to stay here . 5 当从句或主句放于句首时，用 whether ，不用 if . Whether this is true or not , I can't say . Whether I'll have time to go with you I am not sure 6 引导表语从句用 whether ， 不用 if . The problem is whether we should go home or not 8 作 discuss 的宾语，用 whether ， 不用 if . They are discussing whether they should open the door 9、当表示“如果”时用 if,而不用whether 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 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. The point is not who said the words, _____ they are true or not. A. but whether B. and whether C. but how D. and how 14. “What did he ask you?” “_____ I would be late.” A. That B. When C. Where D. Whether 15. He treated all the people around him,______he knew or he didn't know,______. A. if, friendly B. whether, friendly C. if, in a friendly way D. whether, in a friendly way 16. At the meeting, we discussed _____ we should employ more workers. A. if B. whether C. that D.不填 Answers: BADDC ABCAB ABADD B 本文来源：https://www.wddqw.com/doc/b53d464df8d6195f312b3169a45177232e60e44d.html