The earlier sentence was "vous lisez les lettres des petites filles", which was a possessive case (the little girls' letters = the letters of the little girls).
In that sentence "des" was the contraction of "de+les" = of the, and not the plural of "une".
- je vois une petite fille - je vois des petites filles = I see a/one little girl - I see (some) little girls
- les lettres de la petite fille - les lettres des petites filles = lit. the letter of the little girl - the letters of the little girls.
Yeah, you're right. The only way I knew when it would most likely be plural for sure is when I was learning the plurals section. I almost wish there were pictures to describe what needs translating, for context, since the sounds are often very difficult to decipher. I guess that may be something that comes with more practice.
I got this wrong too. As SiteSurf says above des turns to de if there is an adjective before the plural. See http://french.about.com/od/grammar/a/de-vs-du-de-la-des_2.htm bullet 5 for an explanation.
- When the plural indefinite or partitive article is used with an adjective that precedes a noun, des changes to de.
J'ai des amis. - J'ai de jeunes amis. I have some friends. - I have some young friends. (Note: J'ai un jeune ami. - I have a young friend.)
J'ai mangé des épinards. - J'ai mangé de bons épinards. I ate some spinach. - I ate some good spinach. (Note: J'ai mangé de la bonne sauce des épinards. - I ate some good spinach sauce.)
If we are to say, "il mange de bons fruits" and "il mange un bon fruit", does that mean we should not say, "il mange du fruit" but "il mange un fruit"? If this is so, then why do we say, "il mange de l'oignon" and not "il mange un oignon"? Please can someone throw some light on this because I am a little confused here? Thank you very much.
"les jupes des petites filles" (= lit. the skirts of the little girls): in this case "des" is the contraction of "de+les" so it will not further contract to "de".
"j'ai vu des filles, de petites filles" is the plural of "j'ai vu une fille, une petite fille"; so "de" stands for indefinite article "des" which contracts to "de".
the French "fruit" is a regular, countable noun:
-un fruit, deux fruits, le fruit, des fruits, les fruits.
the singular of "de bons fruits" is "un bon fruit", ie "one good fruit"
with no adjective, the plural of "un fruit" is "des fruits" (more than one, some)
with an adjective in front of the noun, "des fruits délicieux" becomes "de délicieux fruits"
I agree. For those trying to learn English: fruit is rarely used in the plural form. It doesn't matter how many peices of fruit there are, you would still just say fruit. You would only say fruits if you were trying to emphasize that there are different kinds of fruit involved.
For example: if there are a group people eating apples and oranges and bananas, you would typically just say "they are eating fruit", however if it was important to convey that there were different kinds of fruit invovled, you might say " they are eating various fruits"