French language Q&A Forum

Bonjour! Thank you for this great lesson and video about using "en!" I have a question about whether or not it's acceptable to repeat the noun when it's in a quantity phrase. To illustrate, for the sentence Elle apporte une bouteille de vin, which one of these is correct, or are both acceptable: Elle en apporte une bouteille. / Elle en apporte une.  I have a similar question with the phrase "des tranches de." My guess is that since "des" is a partitive, the noun "tranches" wouldn't follow the verb because "en" replaces the whole "des" phrase, but I'm not 100% sure. So Il mange des tranches de gateaux would become "Il en mange" and not "Il en mange des tranches"? Or are both acceptable? 

I'm reading an example using merci de with an action already done. It says to use Merci de + [Infinitif Passé] and gives the following example:

C'était très difficile, merci de m'avoir aidée.

Please, can you explain why aidée is feminine?

When do we use marron or brun for the color brown? 

Hhello what is the difference between eventail and gamme paul 

Quel est le meilleur aspirateur? is a usage  ( non action )

where as Laquelle de ces bouilloires marche le mieux?  uses a verb action ?  i.e the kettle works  ?