Construction 'if ... or not'

[Nessie]

Hi,
Can we say ‘if…or not’? Does it have the same meaning as ‘whether… or not’?

Many thanks
Nessie.

[Alan]

Hi Nessie,

Could you please put this in a context.

Alan

[Yankee]

Hi Nessie

Yes, you can use ‘if … or not’. However, ‘if’ is not always interchangeable with ‘whether’. Have a look here.
.

[Nessie]

Hi Alan, let me put it in a context:
I don’t know whether she’ll come or not
I don’t know if she’ll come or not

Hi Amy,
So you mean:
1/ ‘if… or not’ is correct, but ‘whether… or not’ is more preferred?
2/ only ‘or not’ can be used with ‘if’? (which means this is wrong: ‘I don’t know if she will go to school or stay at home’)

[Nessie]

But, Amy, I can’t understand this:

Note - The word IF does not always signal a conditional sentence. In such cases, the GMAT prefers “whether” instead of “if”

I don’t know if I will go to the dance. (Incorrect)
I don’t know whether I will go to the dance. (Correct)

=> Why is the former sentence incorrect?

[Atomos]

Hi, nessie

Note - The word IF does not always signal a conditional sentence. In such cases, the GMAT prefers “whether” instead of “if”

I don’t know if I will go to the dance. (Incorrect)
I don’t know whether I will go to the dance. (Correct)

In my opinion, Simple Future is rarely used in IF clause unless it’s for emphasis. So in this particular case, “whether” is way more preferred.

[Yankee]

@nessie

But, Amy, I can’t understand this:

Note - The word IF does not always signal a conditional sentence. In such cases, the GMAT prefers “whether” instead of “if”

I don’t know if I will go to the dance. (Incorrect)
I don’t know whether I will go to the dance. (Correct)

=> Why is the former sentence incorrect?

Hi Nessie
What they are telling you is that the GMAT (a standardized test) will likely mark that usage of “if” as incorrect because the sentence is not a conditional sentence.

@nessie

So you mean:
1/ ‘if… or not’ is correct, but ‘whether… or not’ is more preferred?

No, I mean “if … or not” can sometimes be used. It depends on the structure of the sentence, and it can also depend on whether your sentence is informal or formal.

@nessie

2/ only ‘or not’ can be used with ‘if’? (which means this is wrong: ‘I don’t know if she will go to school or stay at home’)

No, you will also hear “if” used the way you used it in the sentence. However, I’d say it sounds more informal than using “whether”.
.
.

[Nessie]

Hi Amy,

The question is if the man can be trusted. - Correct but less preferred

=> Why is it correct but not preferred, Amy? Is it because it’s less formal?

What they are telling you is that the GMAT (a standardized test) will likely mark that usage of “if” as incorrect because the sentence is not a conditional sentence

=> Surely it’s not a conditional sentence, but I still don’t understand why it’s wrong. ‘If’ is not always used in conditional sentences, is it?

No, I mean “if … or not” can sometimes be used. It depends on the structure of the sentence, and it can also depend on whether your sentence is informal or formal

=> Now I understand that the use of ‘whether’ is more formal, but as for ‘“if … or not” can sometimes be used’ and ‘It depends on the structure of the sentence’, I’m still not very clear, Amy. I know you’ll tell me to re-read the page. I’ve done it but still not very clear.

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

The Directors have not decided whether they will recommend a dividend or reinvest the profits.

=> So’if… or’ (including ‘if… or not’) can still be used (and considered correct), but not as formal as ‘whether… or…’?

I can’t understand why this:
I don’t know if I will go to the dance.

is wrong while these:
I’m not sure whether / if I’ll have time.
I don’t know if / whether I can help you
are right…

Thank you very much,
Nessie.

[Torenable]

Hi nessie

In GMAT grammar, “or not” should not be added to a conditional clause, cause “whether” itself has contented the meaning of “or not” and doing so would made sentence wordy.