List menu and sub menu
If your question is not what your title says consider this:
Module you need is views module.


Create a view of article type and keep the display of  your view type as page,this view will list all nodes of article content type.Give page path as "articles" or whatever.
Create another view to show taxonomy terms of type all/vocab, this view will also be page display type.Give page path as "show-taxonomies" or whatever.
Create a menu block with two menu items "articles" and "others" link them respectively to the views page path you have set.
Now put this menu block in main content region with path specified for block display as "opinions".