French partitive and definitive articles are explained in terms of set theory. Also, a theory regarding the reduction of the partitive article to "de" in certain circumstances is presented.
The four cases in which the partitive article gets "reduced" (i.e., from its full form to a simple "de"): after a negative adverb, after a quantitative expression, with a preceding plural adjective, and in compléments prépositionnels.
Canada's national anthem in its original form. A good deal less bloody than la Marseillaise, and much easier to sing than O Say, Can You See.