sentence

[cleopenelope]

Hi again

His sentence has been commuted to 6 months on the...............of failing health.

1. bases
2. causes
3. grounds
4. reasons

[Miner49'er]

Law student?

Hi again

His sentence has been commuted to 6 months on the grounds of failing health.

1. bases
2. causes
3. grounds
4. reasons

[BobK]

Hi again

His sentence has been commuted to 6 months on the...............of failing health.

1. basis
2. causes
3. grounds
4. reasons

1 is still wrong, but it's not as wrong as bases.

Miner49'er is right of course.

b

[Miner49'er]

Oléé !!!

[cleopenelope]

Thanks again for Bobk and Miner49'er.

[queenbu]

grounds=the reason for doing or believing something e.g.He resigned on medical grounds.
I refused on the grounds that(=) because it was too risky.

basis=the reason for something. Marks are awarded on the basis of progress and performance.
There is no legal basis for his claim.

basis=a situation, fact, or idea from which something can develop. Dani's essay can serve as a basis for our discussion.

Why is 'on the basis of' wrong in cleopenelope's post?

[Casiopea]

Reason as in the underlying fundamental assumption(s); e.g., 'progress and performance', 'Dani's essay'; Cf. 'failing health', ?She was fired on the basis of failing health.

[BobK]

...
basis=the reason for something. Marks are awarded on the basis of progress and performance.
There is no legal basis for his claim.
basis=a situation, fact, or idea from which something can develop. Dani's essay can serve as a basis for our discussion.
Why is 'on the basis of' wrong in cleopenelope's post?

I'd correct your first definition to basis=the reason for something to be made/done/ensured: in that example, progress and performance are the reason for the award to be made. Going back to the original sentence, His sentence has been commuted to 6 months on the basis of failing health. would mean something like the sentence was commuted only on the understanding that the criminal would take steps to ensure failing health!

As Casi's '?' indicates, though, people are beginning to accept what seems to me to be an error due to a misunderstanding based on dictionary definitions that over-simplify by saying things like 'basis = reason'.

b

[queenbu]

an error due to a misunderstanding based on dictionary definitions that over-simplify by saying things like 'basis = reason'.

In fact, my/the definition which you corrected came from 'Cambridge Learner's Dictionary'.

I'm still trying to figure out the rest. I admit, this time I am a bit confused.
Thanks, both.

[Casiopea]

I'm still trying to figure out the rest. I admit, this time I am a bit confused.
Thanks, both.

You're welcome, queenbu. Remember, though, there's the Standard and then there's colloquial usage. The part where the latter becomes the former, we won't see in our lifetime. Change, especially swaying the opinions of the masses in White Towers, takes time - a long time. The best we can do (to survive) is accept that there are two sides, even three, four, and more if you count dialects and idiolects.