French language Q&A Forum

Speaking to friends, would it not be correct to say: 'Dépêche-toi', rather than 'Dépêchez-vous'?

As I know we use "en" to replace a noun that follows number/quantity such as un(e), deux, un peu de etc.. so in this case it means that I can use "en" to replace ANY noun including "idée, histoire, conseil, chance" etc but only with any indefinite article, right? And in examples like "je vais vous donner une idee" "il raconte une histoire à mon ami" these nouns can be also replaced with "en", right? or not? why? I passed several tests where these nouns were replaced with COD(le,la,les) and I really can't understand why.. can someone explain it to me, please?

good reading exercise for young readers 

il raconte une histoire à mon ami- il lui en raconte (or it should be  il la lui raconte"?) if it's 2d option, could you please explain why? thank you!

Can someone tell me what the difference between trop de(too much) and tant de(so much) is? I know the meanings of both , but unsure how to use them in sentences.

The quiz question

which leads to this lesson is ambiguous in my opinion. I selected Non, je n'ai pas un enfant purely because I would have expected the english for je n'ai pas un enfant to be I don't have children instead of no, I don't have a child. They have slightly different meanings and I believe my answer to be more accurate. I stand to be corrected on that though?

Could someone please explain what "aidée" is agreeing with here? Why is it feminine?

Am I able to say "Avez-vous décidé?'' instead of "Avez-vous fait votre choix ?" in this  exercise?