How do I know when to use de or des when asking a question using "combien"? For example, in the second counting lesson in the Language and Culture section, when asking how many apples (plural) are in the refrigerator, I would think "des" would be used because it is plural, rather than "de", yet the lesson indicates the use of "de".

In Lesson 11.7 on exclamations, the explanation says: "Last but not least is « combien » which means "how much" or "how many." It must be followed by an adverb, or de + noun." The examples were "Combien de fois te l’ai-je dit !" or "Combien de robes as-tu !" So even though it doesn't explicitly say that when using combien as a question, I believe it follows the same "de + noun" rule.

I have exactly the same question as Allen D10, March 27, 2013 regarding the use of de and des with combien but did not understand the answer provided by toru25. Can someone elaborate please?

Bonjour à tous! Yes, as Toru25 said the formula for questions using 'combien' is: Combien + de + noun For example: Combien de langues parles-tu? The noun that follows 'de' is always plural because remember you are asking how many but despite this 'de' doesn't change. No matter whether the noun following 'de' is plural or singular, 'de' always remains 'de'. This is the same as the structure, beaucoup + de + noun ( a lot of ... ) For example: J'ai beaucoup de chiens (I have a lot of dogs) Despite the fact that noun is plural, 'de' doesn't change. I hope this helps! - Marie-Claire

Would this hold also for other expressions of quantity, like ... au moins de ... ... un peu plus de ... ?

Bonjour Lancish! I am very sorry for the late reply. Yes, you are right. Most fixed expressions such as these do not change. However, French is a language of exceptions so I would not be surprised to come across one from time to time. Keep up the good work! - Marie-Claire