I need some help with SQL structure.
I write articles and want to share them online in my web site, that users could comment on them.

Each article contains name, paragraphs, sections and blocks of content.
You can look at it as a tree: article => paragraphs => sections => blocks of content.
each article has many paragraphs, each paragraph has many sections and each section has many blocks of content.

Now, i would like that users will be able to add their comments for every level in the tree.
In order to do so i created a table for each entity (article, paragraph, sections and blocks of content) that holds static information .

My question is what is the best way to handle the dynamic part, where to store the users' comments?
what is the best solution here?

Thanks.