来 源初 中教 师*网 w Ww.9 1 0w.net 一般可通用。
I don't know whether/if they will come to help us.
但是,当whether与or not连成一个词组时,whether不可换用if。
I don't know whether or not they will come for our help.
若whether和or not不连在一起,在口语中可以用if取代whether,当然也可以用whether。
I don't care if/whether your car breaks down or not. 我不在乎您的车是否是会出故障。
此外,还有三种情况值得注意:
(1)在介词后面只能用whether,不能用if。
I am not interested in whether you'll come or not.
(2)在动词不定式之前,只能用whether,不能用if。
He doesn't know whether to stay or not.
(3)在及物运动discuss后的宾语从句中,只能用whether,不能用if。
We discussed whether we should make a change in our plan. 来 源初 中教 师*网 w Ww.9 1 0w.net
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