"will" in if-clause

I would appreciate your help very much with the following questions.
If you won't helpus, all our plans will be ruined. 1.
If you will use it, you can have it. 2.
Does the "will" in the if clause of 1 and 2 have modal meanings, which may be "want to do, or willing to do"?

If drugs will cure hime, this should do the job. 3.
What does "will" mean in 3.?

If you won't arrive before six, I can't meet you. 4. My grammar book explains the if clause as "If you won't be arriving before six"

If the game won't be finished until ten, I'll spend the night at your place. 5. The explation given by my grammar book is "If the game is not going to be finished until ten"

If the water will rise above this level, then we must warn wverybody in the neighbourhood. 6. My grammar book says "if the water is going to rise above this level, then we must now plan to warn everybody in the neighbourhood."

If we definite won't win, why should we bother to play? The explanation is: "If we definitely aren't going to win, ..."

Besides the questions about 1,2 and 3, I have quite a few about 4, 5, and 6.
Questions about 4: What does the "will" mean? the grammar book's explanation is in the future progressive tense, why the tense be used here? Can the if clause be changed to "if you don't arrive before six"?

Questions about 5: The meaning of "will", Why is it interpretated as "if the game is not going to be finished until ten"? Can the game plan itself? Can the if clause be changed to "if the game isn't finished until ten"?

Questions about 6: Why is "will" used in the if clause? is it a modal? Does it mean we don't want to win? "to be going to " in the explanation sounds strange, can the if clause be changed to "if we definitely can't win" or "if we definitely don't win"?

These sentences are taken from my grammar book, I don't understand what is said about them. Thank you very much for your help. Mei

Yes, welcome, Mei!

To supplement rather than contradict Paco's analysis:

1. If you won't help us, all our plans will be ruined.
— Here 'will' is used to express 'be willing to', rather than a future tense.

2. If you will use it, you can have it.
— You could read 'will' as 'intend', i.e. 'if you intend to use it, you can have it'.

Strictly speaking, this isn't an ordinary conditional, since 'having it' precedes 'using it'. You could rephrase it:

'Provided that you use it, you can have it.'

3. If drugs will cure him, this should do the job.
— You could take it as a variant on a type '0' conditional ('If ice melts, it forms water'), e.g.

'If drugs can cure him, this can cure him.'

4. If you won't arrive before six, I can't meet you.
— In standard conditional statements, we have a condition in the IF clause, and the consequence of meeting that condition in the main clause, e.g.

'If you scratch my back, I'll scratch yours.'
'If I were you, I'd find another job.'

But other kinds of IF statement are intended to express an inference, rather than a condition. So we have a fact in the IF clause, and an inference in the main clause. That's the case here. We can test it by replacing 'If' with 'Since':

'Since you won't arrive/won't be arriving before six, I can't meet you.'

(Note that 'if' can't be replaced with 'since' in true conditional statements.)

4a.Can the if clause be changed to "if you don't arrive before six"?
- Yes!

5. If the game won't be finished until ten, I'll spend the night at your place.

– Again, not strictly a conditional IF. Really, the speaker means:

'Since the game won't be finished until ten, I'll spend the night at your place.'

5a. Can the if clause be changed to "if the game isn't finished BY ten"?
- Yes; but then it makes a condition of the IF clause, and so changes the meaning.

6. If the water will rise above this level, then we must warn everybody in the neighbourhood.
— I would disagree with your book about this one. I wouldn't myself use 'will' here. Indeed, as the sentence stands, it could be interpreted as either:

'If the water rises above this level...' (i.e. it's still only a possibility)

or

'If the water is going to rise above this level...' (i.e. it's certain).

Presumably the second interpretation is intended, i.e.

'Given that the water is going to rise above this level, we must warn everybody in the neighbourhood.'

MrP

Hello Paco

How do conditional statements work in Japanese?

(I'm not convinced that "type 1/2/3 etc" is the most helpful way of presenting conditionals; maybe there's a way of explaining that would be easier for Japanese people.)

MrP