help with article use

[wynnmyintuu]

It is said in grammar books that a noun followed by a modifying phrase or clause needs a definite article (the). But I find many instances in which a noun with a modifying phrase or clause after it takes an indefinite article.
e.g. On the wall are frescos depicting episodes from the life story of Ramayana.
Could you please explain that for me? Thanks in advance.

[Raymott]

It is said in grammar books that a noun followed by a modifying phrase or clause needs a definite article (the). But I find many instances in which a noun with a modifying phrase or clause after it takes an indefinite article.
e.g. On the wall are frescos depicting episodes from the life story of Ramayana.
Could you please explain that for me? Thanks in advance.

There are no indefinite articles in your "example", so it isn't one.
In any case, the rule you cite is wrong.
A man with a wife and children carries a heavy burden.
Here, the indefinite article is used for 'man', and 'man' is qualified by a prepositional phrase "with a wife and children". And it's correct, at least in grammar.

Do you have an exact quote of this 'rule' from a grammar book ?

[wynnmyintuu]

Thank you for pointing out my error. Actually I haven't found any explicit rule telling that a noun with a modifying phrase or clause needs a definite article. What I found was this exercise:
"Join the following sentences.
A man was injured. He has been taken to the hospital.
Answer: The man who was injured has been taken to the hospital."
Would you kindly explain to me why "a" is changed into "the" in the example, please?

[Raymott]

Thank you for pointing out my error. Actually I haven't found any explicit rule telling that a noun with a modifying phrase or clause needs a definite article.
It's probably best under circumstances like this not to assume such a rule, then.

What I found was this exercise:
"Join the following sentences.
A man was injured. He has been taken to the hospital.
Answer: The man who was injured has been taken to the hospital."
Would you kindly explain to me why "a" is changed into "the" in the example, please?

No, I can't explain why this was done.
The exercise can be completed correctly by writing, "A man was injured and has been taken to hospital".

But I suspect that there's more to it - for example, the exercise might follow a lesson on subordinate clauses; or an example template has been given which changes 'a' to 'the' because by the time the man has been taken to hospital, the man is known, and hence is referred to by 'the'.

Other than that, one could appeal to incompetence, mediocrity or a general lack of care, foresight or attention to detail - all of which are common human failings and seem to affect writers of ESL exercises disproportionately.