126.96.36.199.3 Use of de la, du, des as partitive articles
As we just have defined to regard des as partitive article, we now have three of them du, des and de la. We now see the partitive article as something that refers to something uncountable in singular, and a group of single items seen as a unit if plural. We extended the definition to come to the point to say when to use the partitive article:
As a basic rule (with a few exceptions) the partitive article is used when in English there is no article used, but 'some' can be used.
Then there is something that might have crossed your mind already. If there is a reduction of an article with a following vowel and a reduction in a partitive article, which goes first?
Since the reason for reduction is the easier pronunciation and pronouncing two vowels after another are hard to pronounce, this is avoided by using the reduction of the article and then there is no reduction for the partitive article anymore..