Definite article after "of"

Question

From what know, every countable word needs to have an article. If I would write the sentences below, I would use the definite article after each "of" word.

.. end of the every sentence... end of the each month. 

Put a period at the end of every sentence.

I pay the phone bill at the end of each month.

I know that there are some exceptions by generalizing or when a word is representing some class but I don't think that this is the case.

Why the author of these sentences just omitted the definite articles?

Answer 1

The words "every" and "each" are replacing the article.

Other adjectival pronouns could be used e.g. "that", "my", "his" etc. - all of which would obviate the need for an article.