if

if

1. If is followed by the subjunctive form were (instead of was) when the condition it introduces is hypothetical or impossible to fulfil, as in If I were younger, I'd travel the world. Was is used (1) informally in such cases (If I was younger, I'd travel the world), and (2) to indicate past tense in which the condition is capable of fulfilment (If I was younger, I wasn't any wiser). Use of the subjunctive form be (instead of am, is, or are) is now decidedly old-fashioned: If this be true, all is not lost. See subjunctive mood.

2. If and whether are both used to introduce noun clauses as in Tell me if / whether you can come, but whether is regarded as somewhat more formal and is preferable in avoiding possible ambiguity (in the sentence just given, a possible interpretation, though not the natural one, when if is used is ‘If you can come, tell me (some other thing)’.

3. If and though are both possible in constructions of the type a cheap, if/though risky method, although again there is sometimes a small risk of ambiguity in the use of if.

4. If is sometimes used in a clause without any continuation, either as a way of making a strong assertion or as a polite request. This use is normally limited to conversation:

• Well, if that isn't the best thing I've heard since I was home —Compton Mackenzie, 1919

• ‘There's your tea. Drink it.’…‘If I could have another lump of sugar.’ —Graham Greene, 1988

• Natasha, if I could see you for a minute, please —fiction website, AmE 2004 [OEC].