A Question of 'of' possessives.

[stagger]

Hello
My first post here.

I am a British English teacher currently in Tainan, Taiwan, and I have a question....

I might be thinking too much about this, and missing the glaringly obvious, but....
Is there any kind of rule for 'of' possessives? For example, one might say 'the school's toilets are very dirty', but probably not 'the toilets of the school'. However, nobody, I think, would say 'the mouth's roof', but rather 'the roof of the mouth'.
It's difficult to search for on the net, and I can't find anything sufficient.
Is there a rule, or is it merely instinctual? Am I missing something?

[freezeframe]

Hello
My first post here.

I am a British English teacher currently in Tainan, Taiwan, and I have a question....

I might be thinking too much about this, and missing the glaringly obvious, but....
Is there any kind of rule for 'of' possessives? For example, one might say 'the school's toilets are very dirty', but probably not 'the toilets of the school'. However, nobody, I think, would say 'the mouth's roof', but rather 'the roof of the mouth'.
It's difficult to search for on the net, and I can't find anything sufficient.
Is there a rule, or is it merely instinctual? Am I missing something?

You can search the forums as there are many discussions on this already posted.

[stagger]

Thanks for your informative answer, key member.

[freezeframe]

Thanks for your informative answer, key member.

No problem.