Whether or If

May 31, 2011pdf

Both whether and if can be used to introduce indirect yes/no questions.

  • I don’t know whether I can come. OR I don’t know if I can come.
  • I don’t know whether I will have time. OR I don’t know if I will have time.

After some verbs, whether is preferred to if.

  • We discussed whether we should move to another city. (More normal than ‘We discussed if we should…)

Whether is usually preferred in a two-part question with or.

  • I don’t know whether I should accept or refuse. OR I don’t know if I should accept or refuse.

If cannot be used after prepositions.

  • We haven’t settled the question of whether we should move to a bigger city. (NOT We haven’t settled the question of if we should move to a bigger city.)

Whether is used before to-infinitives. If cannot be used before to-infinitives.

  • I don’t know whether to accept or refuse. NOT I don’t know if to accept or refuse.

If is not normally used to introduce a clause used as subject or complement.

  • Whether we can trust our guide is another matter. (More natural than ‘If we can trust our guide is another matter’.)
  • The question is whether our guide can be trusted.

Note that if is possible in a very informal style.

  • The question is if our guide can be trusted.
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