"How many skirts do you have?"
Translation:Combien de jupes avez-vous ?
Why is "Combien de jupes est-ce que tu as ?" marked wrong? Is it incorrect to use est-ce que with combien? This site says it's okay. https://www.thoughtco.com/french-interrogative-adverbs-1368800
Yes on all counts - none of what you have written is accurate French. Apart from spelling errors making it hard to differentiate from the grammatical errors, the structure is all wrong.
Combien = "how much or how many" eg Combien ça coûte ? → "How much is it"?" / "Hou much does it cost?
Combien de, (like combien), is an adverb of quantity only that is followed directly by a noun as in the given sentence:
Combien de jupes avez-vous ? / Combien de jupes as-tu ?
TO GIVE YOU SOME BACKGROUND INFORMATION
Imprecise quantities are expressed using adverbs of quantity, which are usually followed by the preposition de.
Il a beaucoup de chiens. — He has a lot of dogs.
Il boit trop de bière. — He is drinking too much beer.
Combien de jupes as-tu ? — How many skirts do you have?
No matter whether the noun following de is plural or singular, de always remains de.
However, other articles can follow adverbs of quantity when the noun is specific.
Beaucoup des (de + les) amis de mon frère sont là. — Many of my brother’s friends are here.
Je veux plus du (de + le) même. — I want more of the same.
This latter case does not apply to this sentence as the speaker is asking about skirts in general - there is no specificity.
I hope that helps.
Thank you so much for the time you have given me... Ripcurgirl and so sorry about the spelling mistakes... it is the typing errors that often catch up with me in this course....but my question was really the difference between de and des... as I understood that " de" stands for singular and plural... I only get confused when I use "des" as plural for the indefinite article... like "des" jupes instead of "de" jupes ... I cannot wait until I am so " pro " like you are.... and thank you again for your time
But in other instances of generality you keep articles e.g. I like chocolate is j'aime le chocolat. In almost all cases French adds articles when many languages would not (I drink beer = Je bois de la biere). Just seems with "how much of" does it lose it, and then only sometimes. Quite confusing!
The definite article is kept in J'aime le chocolat because the sentence uses a verb of "appreciation". This rule holds true for all verbs that express this characteristic - eg the French counterparts of : adore, love, like, appreciate, prefer, hate, detest, loathe, etc ...
Combien de is an adverbial phrase and as such never uses an article when followed by a noun.
Another example of this format is J'ai beaucoup de fleurs.