Sorry! May I come in this?

I think the point is the same as this case.
[NG] Which is your book?
-> Which book is yours?
[NG] This is my book.
-> This book is mine.

[NG] These are too tough questions to answer.
[NG] These are too tough questions.
-> These questions are too tough (to answer).

[NG] It's too dirty water to drink.
[NG] It's too dirty water.
-> The water is too dirty (to drink).

Are my thoughts rubbish?
All the best.

Hello Casi

I would not quite agree with your thoughts on 5 and 6, since 'of' could not be inserted here; you could only say 'it's too dirty a glass to use'/'too tough a question to answer'.

'Dirty of', 'tough of' have another meaning:

'That's very dirty/tough of you' = 'you are being very dirty/tough'.

MrP

These are my thoughts on the structure...Please feel free to comment adversely.

---

The underlying structure of the 'normal' form is:

[article/demonstrative/possessive pronoun] [noun] [copular verb] too [adj] to [verb]

e.g.

1. 'The question is too difficult to answer.'
2. 'The goalkeeper is too easy to beat.'
3. 'That knot looks too hard to untie.'
4. 'My painting seems too good to sell.'


The underlying structure of the 'emphatic' form is:

[pronoun/demonstrative/poss. pronoun] [copular] too [adj] [indefinite noun] to [verb]

e.g.

1a. 'It is too difficult a question to answer.'
2a. 'He is too easy a goalkeeper to beat.'
3a. 'That looks too hard a knot to untie.'
4a. 'Mine seems too good a painting to sell.'

In moving from the normal to the emphatic, we make the following transpositions:

i) 'the + noun' > a pronoun
ii) 'demonstrative adj. + noun' > demonstrative pronoun
iii) 'possessive pronoun (first form) + noun' > poss. pronoun (second form) — e.g.

'The painting' > 'It'
'The goalkeeper' > 'He'
'That knot' > 'That'
'My painting' > 'Mine'

The noun itself, meanwhile, becomes 'indefinite' — in effect, a representative of a kind, e.g. 'a question', 'a painting'. You could say the 'emphatic' versions are implicitly as follows:

1b. 'It is too difficult a [type of] question to answer.'
2b. 'He is too easy a [type of] goalkeeper to beat.'
3b. 'That looks too hard a [type of] knot to untie.'
4b. 'Mine seems too good a [type of] painting to sell.'

Thus plurals and uncountables (which can't take an indefinite article, or act as representatives of a kind) behave oddly in this structure:

5. 'The shoes are too difficult to keep clean.'
6. 'Water seems too ordinary to sell.'
7. 'Drugs are too easy to hide.'

Making the transpositions:

5a. 'They are too difficult a shoe to keep clean' — ?'they' vs 'a'
6a. 'It seems too ordinary a water to sell' — ?'a water'
7a. 'They are too easy a drug to hide' — ?'they' vs 'a'; meaning changes

(Surprisingly, googling on versions of this transposed form is unsuccessful, which suggests there's remarkable resistance to it from native and non-native speakers.)

Note that if we try omitting the indefinite article, the emphatic version no longer refers to a representative of a kind, but to a specific case:

5b. 'They are too difficult shoes to keep clean.'
6a. 'It seems too ordinary water to sell.'
7a. 'They are too easy drugs to hide.'

Interestingly, there are also 'emphatic' forms with no reasonable 'normal' form:

8a. 'You are too good a cook to sack.'
8. ?'The cook (who is you) is too good to sack'/'You as a cook are too good to sack'.

MrP

Hello Paco

Sorry, the square brackets were a bit misleading; I meant them as 'interpretation', rather than straight ellipses. (If they represented straight ellipses, someone could legitimately say, you've solved the question of 'it is too difficult a question'; now explain 'too difficult a kind'!)

I meant to bring out the 'indefiniteness' of the transposed noun — i.e. the 'thisness' of 'this question' is now wholly embodied in the demonstrative pronoun, while the 'questionness' has become non-specific:

'This question is too difficult to answer' =>
'This is a question of a kind too difficult to answer =>
'This is too difficult a (kind of) question to answer.'

(I notice that this construction may be used with plurals and non-countables:

'These are questions of a kind too difficult to answer.'
'This is water of a kind too polluted to drink.')

Thus the noun in the 'too...a...to' construction seems to depend on 'indefiniteness', whereas the noun in the simple 'too...to' is specific. (As in the example above, where we move grammatically from 'this particular question' to 'a question'.)

'Too much/too many...to' seems to be a slightly different construction. As you say, it relates to failure to 'do' because of quantity, rather than failure to 'do' because of a particular quality (e.g. relative 'difficulty'). As far as I can see, it doesn't involve strict copularity.

Also, the 'too much/many' examples seem to me to belong to the 'specific' class:

'I have too much homework to do' — my specific homework.
'There are too many people to feed' — those specific people.

MrP